Crash on 32 bit JVMs: "Unable to bootstrap datafixers" due to stack overflow
- Increase the stack to 1 MB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1M
- Increase the stack to 1 MB
- Add -Xss1M to the server startup script
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
Environment
Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
4GB ram
Intel Graphics
Windows 8.1 64bit
Java Version 8 Update 171 32bit
Linked Issues
is duplicated by38
MC-129505Game can't startDuplicateMC-129540Minecraft Crashes When Loading 18w19a or 18w19bDuplicateMC-129598can only play in 1.12DuplicateMC-129599StackOverflowError trying to LoadDuplicateMC-129622Game crashes when trying to bootDuplicateMC-129647Game crash at launch (18w20a and 18w19b)DuplicateMC-129650Crashes on start upDuplicateMC-129694Snapshot 18w20a/18w20b crashDuplicateMC-129770Game + launcher crash when opening 18w19a+DuplicateMC-129778Keep CrashingDuplicateMC-130142Unknown Crash when LaunchingDuplicateMC-130167CrashingDuplicateMC-130212When I'm going to open a snapshot, the game stops workingDuplicateMC-13023618W21A WINDOWS CRASHED ON LAUNCHDuplicateMC-130239problem when open serverDuplicateMC-130347game crashes instantly after startupDuplicateMC-130366Changes between 18w16a and 18w19aDuplicateMC-130412Snapshot crashes when startingDuplicateMC-130482Crash on startupDuplicateMC-130490Launcher doesn't launch game or game crashes upon launchingDuplicateMC-130549Stackoverflow after updating to 18w22cDuplicateMC-130573Unable to bootstrap datafixers - starting serverDuplicateMC-130675it crashes as when the mojang logo shows up.DuplicateMC-130762Game crashes while openingDuplicateMC-130777Server crashes "Unable to bootstrap datafixers."DuplicateMC-130797Game Crashes Shortly After LaunchingDuplicateMC-130967Game crash on launchDuplicateMC-131028Minecraft Snapshot Not Launching/Working PerfectlyDuplicateMC-131143Game crash at launch (18w20a and the newest snapshot and pre-release)DuplicateMC-131160Minecraft launcher closes arrived at the written MojangDuplicateMC-131233Can't open 1.13 pre 1DuplicateMC-131259The game crashes before openingDuplicateMC-131285Game Crahes when launching MinecraftDuplicateMC-13134118w19b and above versions crashingDuplicateMC-131498Server crashing immediatly in 1.13-pre2DuplicateMC-131734Stack overflow when running 1.13pre2 on windows 7 32bitDuplicate
MCL-9361Do not run the latest version! V. 2.0DuplicateMCL-95181.13 Pre-1 Will Not Fully LaunchDuplicate
Created Issue:
Game keeps crashing
When trying to open game at 18w19a and b the whole luncher crashes and there is no Crash log for it from game files and windows system
Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
4GB ram
Intel Graphics
Windows 8.1 64bit
Java Version 8 Update 171 32bit
Zrzut ekranu (8).png
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
![[Mod] Neko](../../../data/avatars/users/92901.png){kind=small}
Game keeps crashingCrash: Unable to bootstrap datafixers
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Crash on 32 bit JVMs: Unable to bootstrap datafixers
Workaround
Workaround
- Increase the stack to 1GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1G
Possible cause
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
Workaround
Workaround
- Increase the stack to 1GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1G
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
Workaround
Workaround
- Increase the stack to 1GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1G
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)Workaround
- Increase the stack to 1GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1G
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
Workaround
- Increase the stack to 1GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1
GPossible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)Workaround
- Increase the stack to 1GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1M
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
Workaround
- Increase the stack to 1
GB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1M
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)Workaround
- Increase the stack to 1 MB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1M
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
Crash on 32 bit JVMs: "Unable to bootstrap datafixers" due to stack overflow
![[Mod] violine1101](../../../data/avatars/users/92858.png){kind=small}
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![[Mojang] Georgii Gavrichev](../../../data/avatars/users/22428.png){kind=small}
![[Mojang] Nathan Adams](../../../data/assets/gravatar/dinnerbone.png){kind=small}
[Mojang] Nathan Adams![[Mod] tryashtar](../../../data/avatars/users/41963.png){kind=small}
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Workaround
- Increase the stack to 1 MB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1M
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)Workaround for clients < 1.13-pre2
- Increase the stack to 1 MB
- In the Edit Profile menu in the Launcher, check the JVM Arguments box, and add -Xss1M
Solution for servers
- Increase the stack to 1 MB
- Add -Xss1M to the server startup script
Possible cause
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
The bug
When trying to open game at 18w19a and b the whole launcher crashes and there is no Crash log for it from game files and windows system
[0509/180933:INFO:GameCallbacks.cpp(178)] game/xn (Bootstrap 0) error Unable to bootstrap datafixers java.lang.StackOverflowError at aax$g.a(SourceFile:178) at aax$m.a(SourceFile:525) at aax$m.a(SourceFile:525) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609) at aax$m.a(SourceFile:529) at aao.b(SourceFile:47) at aax$l.a(SourceFile:609)
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I have been unable to run 18w19b and 18w20a because it crashes on startup (MC-129374).
Vlad Rusakov, everything is fine. This ticket was resolved as duplicate of MC-129374
MC-129374 hasn't been fixed yet, but I have been able to get 18w20c working by increasing the stack size.
The issue is still present in 18w20c. I am not getting the WorldGen-Worker error messages in the logs, but the other symptoms are still present: new chunks stop loading and the game can no longer be saved. Environment is 32-bit Java.
To reproduce, try running with limited memory (1Gb) and simply create new terrain by flying in a straight line in creative mode. When the memory reaches its limit, the issue is likely to happen.
For the 1.12.2 to 18w20c issue, see MC-129374 : Install 64bit Java or increase stack.
Assuming fixed since there is no difference between 64bit and 32bit JVM when having 1GB heap available (difference is stack, see e.g. MC-129374, but this is a different story)
Thank you for your report!
However, this issue has been closed as a Duplicate of MC-129374.
It has been linked to this report. If you have additional information, please add it to the duplicated report.
Please search before reporting, as it's likely that one exists already.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki
Thank you for your report!
However, this issue has been closed as a Duplicate of MC-129374.
It has been linked to this report. If you have additional information, please add it to the duplicated report.
Please search before reporting, as it's likely that one exists already.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki
I'm assuming this is MC-129374.
The obfuscated symbols are different, but similar.
satoshi watanabe, this is MC-129374.
Please don't hijack other people's tickets, you don't know if the cause of the ticket author is the same like yours.
This is fixed in 1.13-pre2 version: MC-129374
This is the "server version" of the issue fixed in MC-129374 for the client.
What's the server start command ?
![[Mod] Pokechu22](../../../data/avatars/users/92931.png){kind=small}
Please do not mark issues as private, unless your bug report is an exploit or contains information about your username or server.
Xss1M isn't 1M of thread size; it's 1M of stack size. The default is much less than that; increasing it shouldn't break your server.
This is sort-of a duplicate of MC-129374 (/MC-131498), but it's only apparently happening with servers now (when it shouldn't be happening at all). I'm not 100% sure whether to resolve it as a duplicate or not.
Please attach a crash report so we can further diagnose your issue.EDIT: I'm stupid, nevermind that last bit. Please attach the latest LOG file.
Done
I'm the same way
Happens to me on 18w19a-18w19b
And 18w20a
First: sorry for the duplicate, I actually searched but there were so many "crash reports" that I overlooked this one. But I also failed to search for the keyword "datafixer".
I'd like to add that this also happens on 32bit environments and that I've ruled out a few options:
Hope this can help shed some light on this.
I am also experiencing this crash on Windows 7 with the same Java version as the OP (Java Version 8 Update 171 32bit). Is anyone experiencing this on 64-bit Java or is this a Java 32-bit issue?
It would appear to be a 32-bit issue. I follow Xisumavoid on YouTube, as well as a few other Hermits, and they seem to be able to load the snapshots perfectly. Seriously, Xisumavoid just put out a video highlighting the new 18w20a snapshots a few hours ago.
Edit: I'm also running 32-bit Java on Windows 10. I've also reverted to Java SE 8 Update 111, and still got the same crash.
Looks like we need to add 18w20b to the list of affected versions. Also, the launcher now crashes without adding the errors to the launcher log when you enable the "Open Output Log" option.
Me,too!
It looks like this exception is due to too many thread stacks, overflowing. And it's an type of out of memory.
-The minecraft is dosen't support old computer now.For a better computer. There is no other solution at this time. 
- Add an -Xss1024K may fix you problem.
Impossible man. I got my laptop about 2 years ago
That's the thing: Minecraft would've thrown a java.lang.OutofMemory error if that was the case. Also, ShelLuser tested various memory set ups, and got no results. I can also run Forge mods–some fairly heavy-- on 1G RAM and they run just fine, if slow due to constant garbage collection. And another thing: We all were able to run 18w16a, which means our hardware setups can handle 1.13 when it comes out. But something went seriously wrong when updating to 18w19a+, resulting in in inability to even load the loading screen.
Let's add 18w20c to the list of affected versions.
18w20c Crash report.txt
Guys, I've just hit a workaround for the crashing issues.
In your launcher, go under the JVM arguments for the snapshots, and at the very end, add this argument:
-Xss1024K
This will increase the stack size and allow you to start running the new snapshots.
Robert Byrn:This is a great finding.
On 32 bit JVMs the default stack size is 320k whereas on 64 bit JVMs the default stack size is 1M
Thanks! I'm glad I can help!
Also, you might want to change those G's to M's. We don't want to fry any processors by adding more stacks than they can support, now do we?
Sorry, Kumasasa, but I have another edit for you. I've been messing around with the -Xss parameter in the launcher, and got the snapshots working at as little as 640K for stack size.
Thanks! My server jar would not run (same boothstrap datafixer crash) until I added -Xss1024K.
Think I actually have the 64-bit version of Java...
Minimizing the stack size probably isn't necessary (the difference between 640K and 1024K is fairly insignificant) and could lead to instability elsewhere (if there's something else that uses a lot of stack space), but it's good to know that that can work too.
You can check if you've got 64-bit java installed by running java -version; it should include "64-Bit Server VM" in the output if you have 64-bit java installed (and set as the default version; you might have both 64-bit and 32-bit installed and it's defaulting to 32-bit)
@Ray Allen-- You're welcome! And that is just bizarre, considering that 1024K is the 64-bit stack default.
@[Mod]Pokechu22-- I was just messing around with it after the 1024K modifier locked my game up trying to save and quit. At 640, I was able to save without issue, but the launcher crashed upon exiting. I'll play around some more at 1024 to see if the lock up occurs again.
Add an -Xss1024K fixed my problem.
java -version gives me:
java version "1.8.0_171"
Java(TM) SE Runtime Environment (build 1.8.0_171-b11)
Java HotSpot(TM) Client VM (build 25.171-b11, mixed mode, sharing)
Oh, I guess I should say that my server is just on our home network, not the internet...
Update: Actually tried playing... It works! My kids and I have been unable to play together on our Aquatic world for over a week, but now we're back!
I can confirm that the -Xss1024K workaround has got the 18w20c snapshot working for me after it refused to work without it. Good find.
I'm glad to here that everybody's back to having fun with the new snapshots!
I updated Java from 32 to 64, and it still crashes
Dawid: Did you add the -Xss1024K or -Xss1M argument into the JVM arguments box?
For some reason, this problem occurs because either Minecraft or Java defaults the stack size to the 32-bit default, which is 320K, when the game requires–at minimum in it's current state–640K stack size. So, in order to get the game to run, we have to force the JVM to utilize at least the 640K stack size, preferably 1024K for stability purposes.
This is why we need to add the -Xss1024K tag in the JVM arguments: it will force the game to allocate that much stack space, eliminating the stack verions of an Out of Memory error.
I added this argument after failed try to launching 18w20c with Java 64bit.
Did it help at all?
user-39d6c, do you run Minecraft Client from the Launcher with the bundled Java or do you run a Minecraft server and you're starting maybe a different 32 bit JVM ?
I still can't figure out for sure if I have 64-bit, -version doesn't say.
Looks to me like SE is 64-bit only, so they stopped telling you?
Also, I can't figure out what my default stack size is...
Found a web page that said to type in this: java -XX:+PrintFlagsFinal -version
Doing so says:
{pd product}intx ThreadStackSize = 0
This seems to be impossibly low...
Ok, think I have 32-bit version.
First, it is installed in C:\Program Files (x86)\Java
Second, I did this:
C:\Users\Ray>java -d64 -version
Error: This Java instance does not support a 64-bit JVM.
Please install the desired version.
No idea how this happened, since I have 64-bit OS and browser...
That is weird. Normally, Java downloads the appropriate version automatically.
Ok, seems I switched to IE to install because java doesn't work in Edge. Just learned that IE can have both 64-bit and 32-bit tabs depending on page content. Seems java's automatic detection decided I wanted 32-bit...
Maybe I should uninstall and reinstall 64-bit manually...
Robert Byrn: No, not necessarily. Often the 32 bit version is being downloaded despite being on 64 bit OS.
Ray Allen: Uninstall all Java instances and download here https://www.java.com/en/download/manual.jsp the 64 bit version.
I had changed from 32 to 64, but it still didn’t work. Only way for me to make it work were adding this argument
I did manual install of this version from Oracle:
Java SE Runtime Environment 8u171 (64-bit)
Now, runs fine without the -xss
18w21a
I added the argument at last but it gives error:could not create Java Virtual Machine
@Aman Kasat you must add space before adding this argument
Affects 18w22c
I added the -Xss1024K, so i can now launch the game, but i can't load or create any world, the screen stays on "loading world" (I tested 40 min, still "loading world"). Help ?
Salvatore, this seems to be another issue. Please create a new ticket and attach the launcher_log.txt there.