Hi @ameygodse ,
On setting "Uninstall> Leave",it is supposed to leave the created environment variable as it is.
I couldn't reproduce the issue that you are reporting with Installshield 2020,which version of Installshield you are using?
Can you enable MSI log and see what causes this issue using Releases->Release->Setup.exe->MSI Command-line arguments?
Commandline to get uninstallation log:msiexec /x "C:\Sample\MyPackage.msi" /L*V "C:\log\MyPackage.log"
If possible attach here as well
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