Where Are Windows Setup Logs Stored?
Windows setup and upgrade logs collect in the Panther folder, the first place failed installs explain themselves.
Last updated
Every Windows install and feature update writes its diary to a folder called Panther. The activity log narrates each phase and the error log collects what broke, with timestamps tying them together.
Failed upgrades almost always name their cause in these files. Drivers, disk space, and incompatible apps leave distinct signatures that support articles quote verbatim. Copy both logs before retrying, since a new attempt overwrites the evidence of the last one.
Where Windows stores this, by platform
C:\Windows\Panther
Setup and upgrade logs (setupact.log, setuperr.log). Copy before retrying a failed install; new attempts overwrite the evidence.
Frequently asked questions
Setup failed. Which log do I read?
Open setupact.log for the narrative and setuperr.log for the errors. Search backward from the end for the first failure; everything after it is fallout.
Notice an outdated path? Let us know.