Locate the Setup.exe file for your Adobe app in your Downloads folder.
Last updated on
Dec. 15, 2025
Learn how to resolve error code 21 "System requirements not met" during Adobe app installation on Windows.
Error 21 occurs when your device doesn't meet the minimum system requirements for installing Adobe apps or when Windows Compatibility Mode is enabled, which prevents Adobe installers from running properly.
Windows Compatibility Mode is enabled
Windows Compatibility Mode (WCM) helps older programs run on newer versions of Windows by simulating an earlier Windows environment. However, Adobe installers don't run in WCM, and using them can cause installation errors.
If Compatibility Mode is enabled, follow these steps to disable it.
Right-click the Setup.exe file and select Properties.
Select the Compatibility tab.
Deselect Run this program in compatibility mode for.
Select Apply, and then OK.
Run the installer again.
Note
If disabling Compatibility Mode doesn’t resolve the issue, check that your device meets the minimum system requirements for the Adobe app you're trying to install.
