"could not find or load the Qt platform plugin "windows" in "",



  • Dear community,

    Up to recent, my windows 10 64bit laptop worked fine. However, suddently I get this error after loading certain .exe programs:

    This application failed to start because it could not find or load the Qt platform plugin "windows"in "", Available platform plugins are: minimal, offscreen, windows.
    Reinstalling the application may fix this problem.

    I'm not a coder, I never used the Qt environment ever and other forum entries didn't help so far, since as far as I went down the rabbit hole, this is all about building code in Qt.
    All I like to do is run my programs again. This error occured with multiple programs: MikTex & Texworks and converter tools. So far this error is really denying my work and I have no clue.

    Thanks in advance.

    Kind regards,
    J. Muller


  • Moderators

    @jrmmuller said in "could not find or load the Qt platform plugin "windows" in "",:

    All I like to do is run my programs again. This error occured with multiple programs: MikTex & Texworks and converter tools. So far this error is really denying my work and I have no clue.

    Hi @jrmmuller, the most likely cause here is that your system PATH contains a folder that contains Qt DLLs. Have you installed any new software recently or modified your PATH (shortly before this issue began)?

    If I'm right, then the short version of the solution is this: You must remove the offending folder from your PATH.

    (NOTE: I said "most likely". There are many possible reasons for this error).

    If you do not know how to check and edit your PATH, then we can guide you through the process. However, be prepared: This will involve multiple steps -- I give you some instructions, then you carry them out and report back the details, then I give you further instructions based on what you found, then you carry them out and report back the details... iterating as many times as needed until the issue is resolved.


  • Moderators

    @jrmmuller

    Hi and welcome to devnet forum

    You are right and it is a Qt related issue.

    However, the problem is with an application using Qt and therefore, they are probably the only devs being able to you.
    The problem I see is that they have used a particular version of Qt and part of your installation may have been corrupted by whatever reason.

    The Programs you are listing are probably all from the same open source project and tex related.

    I have MikTex and stuff installed as well, but even though I am a developer and know parts of Qt application development, I would go the route and check the MikTex forum and eventually reinstall MikTex again.



  • @koahnig Hi Koahnig,

    Thanks for your response. Actually it is partly for MikTex, the conversiontools are for converting photo files.

    I tried installing and reinstalling Miktex and trying Texlive, but that didn't help unfortunately.



  • @JKSH said in "could not find or load the Qt platform plugin "windows" in "",:

    @jrmmuller said in "could not find or load the Qt platform plugin "windows" in "",:

    All I like to do is run my programs again. This error occured with multiple programs: MikTex & Texworks and converter tools. So far this error is really denying my work and I have no clue.

    Hi @jrmmuller, the most likely cause here is that your system PATH contains a folder that contains Qt DLLs. Have you installed any new software recently or modified your PATH (shortly before this issue began)?

    If I'm right, then the short version of the solution is this: You must remove the offending folder from your PATH.

    (NOTE: I said "most likely". There are many possible reasons for this error).

    If you do not know how to check and edit your PATH, then we can guide you through the process. However, be prepared: This will involve multiple steps -- I give you some instructions, then you carry them out and report back the details, then I give you further instructions based on what you found, then you carry them out and report back the details... iterating as many times as needed until the issue is resolved.

    Hi JKSH,

    OK, that sounds as that might be the case. Unfortunately I don't know how to edit the path or which could be the cause that modified the PATH. I'm not sure which applications I've installed since the error began.

    If you could help me with the steps, that would be great!

    KR,



  • @jrmmuller said in "could not find or load the Qt platform plugin "windows" in "",:

    If you could help me with the steps

    Open cmd and type echo %QT_PLUGIN_PATH% if it's not empty then delete it (just google: delete environmental variable windows #, where # is your windows version)

    Open cmd and type echo %PATH% and press enter. You'll see a list separated by ; of folder paths. Go line by line and make sure they do not point to a folder that contains a platforms folder that has qwindows.dll in it. If you find such a path edit the PATH variable and remove it (just google: edit environmental variable windows #, where # is your windows version)


  • Moderators

    What version of MiKTeX are you using?

    @jrmmuller said in "could not find or load the Qt platform plugin "windows" in "",:

    If you could help me with the steps, that would be great!

    1. Download ListDLLs from https://docs.microsoft.com/en-us/sysinternals/downloads/listdlls
    2. Extract the contents of the zip file into C:\ListDLLs
    3. Try to launch MiKTeX. When the error dialog appears ("Could not find or load..."), leave it open; don't close the dialog.
    4. Press Windows+R (this launches the "Run" window)
    5. Type "cmd" into the "Run" window and press Enter (this launches the Command Line, cmd, that @VRonin mentioned)
    6. In cmd, type cd C:\ListDLLs and press Enter
    7. In cmd, type ListDLLs.exe miktex and press Enter. You should see a long list of DLLs.
    8. In cmd, type ListDLLs.exe miktex > output.txt and press Enter. You should see a new text file.
    9. Open C:\ListDLLs\output.txt and copy+paste its contents here.
    10. You can close the error dialog now.
    11. In cmd, type echo %QT_PLUGIN_PATH% and press Enter. What gets shown after that? Write it here. (this is related to @VRonin's suggestion)


  • @VRonin

    Hi VRonin,

    I followed your steps and looked up the environmental variable. It turns out that the %Qt_Plugin_path% was indeed set by a certain program (numerical model) which I had installed. I deleted the variable and rebooted the system. As a result all the programs were functioning again without errors.

    Considered this solved. Thanks a lot!



  • @JKSH
    Hi JKSH, I appreciate your help. Thanks to your help and VRonin, my issue has been resolved.

    Kind regards.


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