#2716 MSI Installer not generating uninstall registry key

If you are looking for the decompiler itself, visit https://github.com/jindrapetrik/jpexs-decompiler

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List of issues

Author:

Herobrine24

Date created: 05/16/2026, 9:43:55 pm

Type: question

Visibility: Everybody

Assigned to:

Labels: Installation

State: opened Help

Since version 24.1.1 (the last release distributed as an .exe installer for Windows), the uninstall registry keys no longer appear to be created or updated by the newer .msi installer. This causes compatibility issues for applications use the registry to detect whether FFDec is installed. For example, ME3Tweaks LegendaryExplorer. Notably, 26.0.0 nightly 3515 did generate the uninstall registry key but with a different UUID: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstal l\{0EC217E9-EA69-4B2A-BE5C-A4DD5C48AA4E} (24.1.2 was also tested, since it's technically the last .exe version, but the installer triggered multiple antivirus warnings and still did not create the registry key.)

JPEXS

08/07/2026, 3:48:13 pm

Since nightly 3542, if you want to detect JPEXS is installed on windows (with installer), you can do so by checking HKEY_CURRENT_USER\Software\JPEXS\FFDec\, the value "installed" will be set to 1. There is also "installDir" value in the same key pointing to the directory where FFDec is installed. In nightly 3541 and earlier, the path was incorrectly set to "HKEY_CURRENT_USER/Software/JPEXS/FFDec" - with forward slashes. (and there were no "installDir" value, only "installed") It is better to not check the registry under Uninstall key of Windows\CurrentVersion, since as we use MSI installer, the generated GUID for each version will be probably different. Unfortunately, I cannot set the Uninstall key to a location where there was version 24.1.2 and before, because the GUID has different format - it has InnoSetup (_is) suffix and that cannot be simulated by MSI. We switched to MSI mainly because there were antiviruses that kept marking us as false positives - they did not like the Nullsoft installer (NSIS). MSI seems to have no problems.

State: new→opened
Type: bug→question