Occasionally you may find that a task sequence, package or application has been locked by Config Manager, I normally see this if the console has crashed whilst modifying a task sequence. To remove the lock without waiting for the 30 minute timeout use the following command from PowerShell on your SCCM server:
Unlock-CMObject -InputObject (Get-CMTaskSequence -TaskSequencePackageId <TSID>) -force
where <TSID> is the package ID of the task sequence itself.
Should you receive the error:
Unlock-CMObject : Cannot unlock object. Object context <GUID> is different than the current session context
This means you have missed off the -force parameter