Cook command freezing at DerivedDataCache: Maintenance on build machines

Hey

We’re having some trouble with our CI pipelines with Unreal Engine source builds

The cook command gets stuck seemingly at a derived data maintenance step (Though that could be a red herring)

Our builds usually take ~5-10 minutes, but these get stuck for 2 hours and hit our CI build timeout

The end of our log on unsuccessful builds looks like this:

LogInit: Display: Success - 0 error(s), 5924 warning(s)

LogInit: Display:

Execution of commandlet took: 20.48 seconds

LogCore: Engine exit requested (reason: EngineExit() was called; note: exit was already requested)

LogStaticMesh: Abandoning remaining async distance field tasks for shutdown

LogStaticMesh: Abandoning remaining async card representation tasks for shutdown

LogDerivedDataCache: ../../../Engine/DerivedDataCache: Maintenance finished in +00:00:00.000 and deleted 0 files with total size 0 MiB and 0 empty folders. Scanned 0 files in 1 folders with total size 0 MiB.

LogDerivedDataCache: ../../../Engine/DerivedDataCache: Maintenance finished in +00:00:00.000 and deleted 0 files with total size 0 MiB and 0 empty folders. Scanned 0 files in 1 folders with total size 0 MiB.

Our successful builds don’t have any DerivedDataCache maintenance logs, and instead go on to shutdown subsystems

Our CI build command line invocation is:

RunUAT.bat -BuildMachine -NoP4 BuildCookRun -VeryVerbose -Verbose -unattended -distribution -project=‘C:\agent\_work\18\s/Project/[redacted].uproject’ -archivedirectory=‘C:\agent\_work\18\b’ -targetplatform=Android -servertargetplatform=Android -client -configuration=Test -ubtargs=“-NoUBA -NoUBALocal -UBAResetCas -zenstore -cookincremental -UBALog -UBAPrintSummary -UBADetailedLog -UBADetailedTrace -UBAStrict -UBAForcedRetry -UBAStoreCapacityGb=100 -UBAHost=‘0.0.0.0’ -UBAForceRemote -UBAForcedRetryRemote -UBAHordePool=‘Win-UE5’ -UBAHorde=‘[redacted]’ -CookFlavor=Multi -cmdline=”-tracetailmb=20 -trace=Default" -build -cook -stage -pak -package -archive

Any ideas on why our cook step might be freezing - it does seem to occur more commonly on machines which have previously built development build config (Most of our builds are in Test config)

Hello,

It appears that the editor gets stuck while shutting down. Can you share the full log for a failed and a successful cook for analysis?

We would also need to get more information on the state of the editor process. Could you attach a debugger to the stuck editor, break the execution and save the parallel stack window?

One last thing is that I see you are using the Incremental cook feature. Can you try to turn it off? We have fixed a couple of bugs since version 5.6 and the current recommendation would be to wait until version 5.7 to use it.

Regards,

Martin