I had Qgis 3.4 running well on my PC Windows 10, 64 bit. I tried to upgrade to Qgis 3.8 Zanzibar and I had the error message: ''Qgis_app.dll is missing check runtime environment check C:\OSGEO4W64\bin\qgis-dev-bin-g.exe''.

So far, I tried the folowwing:

  • install countless times with OSGEO
  • install from OSGeo and direct download, the 3.8 don't work
  • go back to the older 3.4 version (from OSGEO or direct donwload), it didn't work
  • run the from the qgis.bat file
  • installed qgis 3.4 as administrator
  • copy and paste the qgis.bat.temp and change the name to qgis.bat
  • Tried to change the path of OSGeo in the .bat file, but I was a little bit lost...?

OSgeo4W shell does not launch from my start menu either, instead I have a text file opening with a text editor software. Grass Gis 7.2 doesn't work also, I also have a text file opening with a text editor software.

Funnily, I have two folders created for QGIS (or I believe so, but I'm not sure):



C:\Program Files\QGIS 3.8\bin

Could this be one of the reason? Should I append one of the path file, if yes, how should I do it?

  • 1
    this is a common problem,try uninstalling all qgis versions and install QGIS 3.8 from OSGeo4W
    – Fran Raga
    Jul 15, 2019 at 10:28
  • Thanks for the suggestion @FranRaga, I tried it, however it returned the same error message (qgis_app.dll is missing etc.)
    – Mel
    Jul 15, 2019 at 23:13
  • So I tried to delete absolutely all my qgis files (including from other session) from my laptop and the C:/drive and do clean start-up with OSGEO. It didn't work. I had the following 4 messages after the install with OSGEO: ''package qgis ltr: qgis-ltr.bat exit code 255''; ''qgis-ltr-comm.bat exit code 255''; '' qgis-ltr-dev.bat exit code 255 '' and; ''qgis-ltr-grass-plugin7.bat exit code 255'' . Any idea?
    – Mel
    Jul 17, 2019 at 9:27

2 Answers 2


I just had this error when trying to start QGIS 3.12.1 through double-clicking on a shp in Windows explorer. I still had old folders for QGIS 3.4 and 3.8, but I'm not sure if that's relevant. Anyway, I deleted those older folders and ran the 3.12.1-installer again. It uninstalled and reinstalled QGIS 3.12.1 and it could now successfully start.


Check your Windows Environmental Variables. • Control Panel\All Control Panel Items\System > Advanced System Settings. Both the "user" and "system" variables may be pointing to older QGIS paths. e.g. C:\Program Files\QGIS 3.06\bin\

Tested:: No, that doesn't fix the problem.

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