Error after update 1.4.7

java.util.concurrent.CompletionException: java.lang.reflect.UndeclaredThrowableException
at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$doSubmit$3(AsyncExecutionAspectSupport.java:279)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1764)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.reflect.UndeclaredThrowableException
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:759)
at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115)
at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$doSubmit$3(AsyncExecutionAspectSupport.java:276)
... 4 more
Caused by: java.nio.file.AccessDeniedException: C:\Users\User\AppData\Local\Gas Powered Games\Supreme Commander Forged Alliance\Game.prefs
at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:89)
at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
at java.base/sun.nio.fs.WindowsFileSystemProvider.newByteChannel(WindowsFileSystemProvider.java:235)
at java.base/java.nio.file.spi.FileSystemProvider.newOutputStream(FileSystemProvider.java:478)
at java.base/java.nio.file.Files.newOutputStream(Files.java:224)
at java.base/java.nio.file.Files.write(Files.java:3491)
at java.base/java.nio.file.Files.writeString(Files.java:3707)
at com.faforever.client.mod.ModService.writeModStates(ModService.java:420)
at com.faforever.client.mod.ModService.overrideActivatedMods(ModService.java:364)
at com.faforever.client.mod.ModService.updateAndActivateModVersions(ModService.java:483)
at com.faforever.client.mod.ModService$$FastClassBySpringCGLIB$$aae9cfd3.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
... 6 more

I deleted all the mods.

Looks like file permissions errors. Check your antivirus

When the antivirus is turned off, the same problem occurs.

Then it is file permissions errors as the client cannot read C:\Users\User\AppData\Local\Gas Powered Games\Supreme Commander Forged Alliance\Game.prefs so check the permissions on that file.

@sheikah I deleted the folder with Gas Powered Games - the problem disappeared. Thanks.