My registry keys 'projectx' folder was messed up, renaming it for a fresh copy allowed me to launch the game again. That was the problem.
Hey there.
To start this off with the required information, my specs are as follows;
Windows 11 Professional Edition
RTX 2060 SUPER 8GB VRAM, 32 GBs of RAM,
AMD Ryzen 9 3950X 16-Core Processor (3.70 GHz)
I can no longer open the game to even reach the log-in screen. The process launches, java.exe runs in task manager, steam will even say the game is running if I try to run it on there... but Spiral Knights itself never opens. I have to end task it manually. It was fine one moment, and then the next when I closed it while looking at my knight on the character select screen, it would no longer open.
I've reinstalled the game, rebooted my PC, rebooted steam, verified files... nothing works.
My projectx.log in the game's folder says this;
2026/08/26 18:56:17:947 INFO P$a.b: Logging to 'C:\SteamLibrary\steamapps\common\Spiral Knights\.\projectx.log'.
2026/08/26 18:56:20:147 INFO P$a.b: Steam initialized.
2026/08/26 18:56:21:704 INFO P$a.b: Init LogonWindow [depl=prod, v=20260826133224, status=null]
2026/08/26 18:56:21:711 INFO P$a.b: We've already tried to choose a knight [ckc=2, discord=false]
Exception in thread "main" java.lang.NullPointerException: Cannot invoke "com.threerings.projectx.client.al.dS(String)" because the return value of "com.threerings.projectx.client.ProjectXApp.Gm()" is null
at com.threerings.projectx.client.bN.wasAdded(SourceFile:220)
at com.threerings.opengl.gui.aD.setRoot(SourceFile:267)
at com.threerings.opengl.gui.P.addWindow(SourceFile:245)
at com.threerings.opengl.gui.P.addWindow(SourceFile:208)
at com.threerings.projectx.client.ui.S.wasAdded(SourceFile:51)
at com.threerings.projectx.client.ProjectXApp.a(SourceFile:630)
at com.threerings.projectx.client.ProjectXApp.c(SourceFile:618)
at com.threerings.projectx.client.ProjectXApp.aQ(SourceFile:1825)
at com.threerings.projectx.client.ProjectXApp.didInit(SourceFile:1314)
at com.threerings.opengl.a.init(SourceFile:393)
at com.threerings.opengl.k.init(SourceFile:563)
at com.threerings.projectx.client.ProjectXApp.init(SourceFile:1234)
at com.threerings.opengl.k.startup(SourceFile:525)
at com.threerings.projectx.client.ProjectXApp.main(SourceFile:252)
Any help would be appreciated, I don't think I can fix this from my side and don't know what else to do.
I have also had this issue. You're a HERO, thank you for this. Your fix worked for me perfectly.
@GH
Detailed Issue Description:
On launch via steam, the launcher window appears, completes verification, and Javaw.exe opens in the background, but the game fails to load to UI/Frontend. No further errors or dialogues are thrown, and the logfile I get from the application matches Niteblade-Eight's logfile exactly.
Workaround:
I have no idea why this error occurred, myself, but after diffing two copies of the same registry key set, it seems that -
Computer\HKEY_USERS\{redacted UUID}\SOFTWARE\JavaSoft\Prefs\projectx : startup-kcount
was set to 2. Setting it back to 1 fixed the issue.
If this is some kind of multi-instance detection, it's badly implemented - I only use one account and one knight at a time, and I was affected by this issue.
@Niteblade-Eight : If you still have your old registry keyset, try to restore it and fix only the Startup KCount value, and that should recover your personal settings if you want them back!