Why is there a registry value created in HKCU\...\AppCompatFlags\Compatibility Assistant\Store after running an application

Question

When I run an application, it creates an entry in HKCU\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Compatibility Assistant\Store. What is this for and why when I uninstall the application, that registry entry remains?

I tried to run this application against Windows ADK's Application Compatibility Toolkit's Standard User Analyzer and it didn't find any issue.

Strangely, after uninstalling Windows ADK, it also left a similar entry in the said registry key.

Answer 1

Hi. Thank you for your question and reaching out. I’d be more than happy to help you with your query

Program Compatibility Assistant (PCA), which allows legacy apps to run on newer versions of Windows despite compatibility issues. PCA identifies program installation errors due to version check mismatches, as well as run-time issues due to deprecated binaries and User Account Control (UAC) settings. PCA attempts to recover from these errors by applying the relevant application compatibility option, which takes effect during the following run. Moreover, PCA keeps a database of programs with known compatibility concerns and alerts users to probable difficulties during program starting.

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Answer 2

Double post