[Qgis-user] Not able to open qt designer after installing qgis via OSGeo4W

[Andrea Giudiceandrea]

> Jochem Kail jochem.kail at uni-due.de
> Mon Feb 16 01:17:47 PST 2026
> The workaround you suggested solved the problem! On my computer 
> msvcp140.dll was located in OSGeo4W\bin and I copied it to 
> OSGeo4W\apps\Qt5\bin.


Yes, you are right, msvcp140.dll is in bin\ not in apps\bin\. It was an 
oversight.


> As an alternative, Thomas Nogatz suggested the following, which also 
> worked: Start the OSGeo4W shell (type "OSGeo..." in Windows search). In 
> the shell, enter "designer and press enter.

Yes, executing the "designer" command in the OSGeo4W Shell will open the 
Qt Designer, even if msvcp140.dll was not copied to apps\Qt5\bin.

Anyway, in such case the "QGIS custom widgets" will be missing in Qt 
Designer.

In order for the "QGIS custom widgets" to be available in Qt Designer, 
you need to start it through the short cut icon or executing the command 
"qgis-designer" or "qgis-ltr-designer" (which correspond to executing 
qgis-designer.bat or qgis-ltr-designer.bar) depending on you have 
installed QGIS or QGIS LTR.

To do that, msvcp140.dll should be copied to apps\Qt5\bin, due to the 
version of Microsoft Visual C++ Redistributable installed in your system.

I've reported the issue to the OSGeo4W tracking system at 
https://trac.osgeo.org/osgeo4w/ticket/909

Regards.

Andrea