Program Compatibility Assistant

Location & availability

C:\Windows\AppCompat\pca\; for example PcaAppLaunchDic.txt and related files

Most relevant to supported recent Windows 11 builds. Files and column semantics can change; examine the actual format.

Fields to examine

• Application path and associated text fields.
• Timestamps interpreted with the format’s timezone and encoding.
• Which PCA file produced the record.

What it can establish

• Support application-launch or compatibility observations recorded by PCA.

What it cannot prove

• Treat all PCA records as the same event type.
• Assume a missing file means the system was cleaned or never ran a program.

Use it in a screenshare

1. Record the Windows build and preserve the original PCA files before sorting or editing them.
2. Determine the schema of each file. Use raw lines beside parsed output to validate path and timestamp interpretation.
3. Correlate a relevant path with Prefetch or process events and distinguish launches from later compatibility processing.

Worked example

A PCA launch record names a utility at a relevant time, while another PCA entry records compatibility handling. Report the launch and later processing separately; neither record describes what the utility did inside the game.

Cross-check the finding

• Prefetch →Support execution of an associated executable within the retained history.
• Security event 4688 →Support process creation recorded by the audited host.

Sources

• Sygnia — original Windows 11 PCA research ↗