Where Are Windows Setup and Upgrade Logs Stored?
Windows setup logs live in Panther folders under $Windows.~BT and Windows, with rollback logs beside them.
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Failed upgrades leave their story in Panther log folders. The active install writes under $Windows.~BT while the running system keeps its own set under the Windows directory.
Setupact and setuperr are the pair that matters: one narrates, the other lists errors. Rollback scenarios add a third location from the reverted attempt. Copy the set before retrying, since new attempts overwrite them.
Where Windows stores this, by platform
C:\$Windows.~BT\Sources\Panther
Current upgrade attempt logs with setupact.log and setuperr.log. The live system mirrors at C:\Windows\Panther, and rollbacks add $Windows.~WS\Sources\Panther. Needs administrator rights.
Frequently asked questions
where do i find why a windows upgrade failed
Open setuperr.log in the $Windows.~BT Panther folder for the error list, with setupact.log beside it for context. The failing phase and error code name the fix.
can i delete windows setup log folders
Yes, once the install is stable. They only aid troubleshooting. Disk Cleanup removes the whole $Windows.~BT tree including the logs.
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