SelfDel function removes uninstaller but is not removing app directory with NSIS - nsis

Question

In order to sign both the installer and uninstaller, I have created a separate uninstaller script as suggested here: https://nsis-dev.github.io/NSIS-Forums/html/t-245688.html. Thus, the uninstaller script not using the WriteUninstaller way to create the uninstaller.
Please note that I am using the SelfDel plug-in to delete the uninstaller, which works successfully; however, it does not actually delete the application install directory even though I am using the /RMDIR option:
Function .onInstSuccess
;SelfDel::Del /REBOOT
;SelfDel::Del /SHUTDOWN
SelfDel::Del /RMDIR
SelfDel::Del
SetAutoClose true
FunctionEnd
Here is the full script for your reference.
!define APP_COPYRIGHT "MyApp © MyCompany 2021"
!define COMPANY_NAME "MyCompany"
!define LANG_ENGLSH "English"
!define PRODUCT_NAME "MyApp"
!define PRODUCT_VERSION "${MAJOR_VERSION}.${MINOR_VERSION}.${PATCH_VERSION}.${BUILD_VERSION}"
!define SETUP_NAME "uninstaller.exe"
# define the name of the installer
OutFile ${SETUP_NAME}
Icon "favicon.ico"
!define MUI_ICON "favicon.ico"
# define the directory to install to
InstallDir "$PROGRAMFILES64\${PRODUCT_NAME}\"
# default section
Section
# define the output path for this file
SetOutPath $INSTDIR
# now delete installed files and registry keys for MyApp
ReadRegStr $0 HKCU "SOFTWARE\${PRODUCT_NAME}" "InstallLocation"
DeleteRegKey HKCU "SOFTWARE\${PRODUCT_NAME}"
Delete $0\config.dat
Delete $0\MyApp.exe
Delete $0\ReleaseNotes.txt
Delete $0\MyApp_LandingPage_114.bmp
Delete $0\MyAppLicense.txt
Delete "$SMPROGRAMS\MyApp.lnk"
DeleteRegKey HKCU "SOFTWARE\${PRODUCT_NAME}"
DeleteRegKey HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\${PRODUCT_NAME}"
DeleteRegKey /ifempty HKCU "Software\Modern UI Test"
SectionEnd
Function .onInstSuccess
;SelfDel::Del /REBOOT
;SelfDel::Del /SHUTDOWN
SelfDel::Del /RMDIR
SelfDel::Del
SetAutoClose true
FunctionEnd
Does anyone have any suggestions on how to get it to delete the app directory? TIA.

Answer 1

So I don't really know the SelfDel nsis plugin that well, but have you tried just restarting your machine after deleting your install-directory like so?
SelfDel::Del /RMDIR
SelfDel::Del
SelfDel::Del /REBOOT
;or just
Reboot
That might help.
Wish you all the best.
Update
Ok so you tried to Reboot.
I researched a little further on the topic and found the same problem, but without the SelfDel plugin: How to solve "The directory is not empty" error when running rmdir command in a batch script?
But maybe you could also try to remove the directory and all the files in the "normal NSIS way" like this:
RMDir /r $YOURDIR
Try this maybe it will work, and perhaps it's just some bug from the plugin.
The SourceForge site of the plugin says it's only testet on Windows 8, so if you are using it on Windows 10 there might be some bugs.
Read the note at the bottom of the SourceForge site: https://nsis.sourceforge.io/SelfDel_plug-in
They say that it is a Trojan Virus and I would recommend to stop using it.
I would seriously consider using another plugin that is testet for Windows 10.
Wish you all the best.