QGIS 3.18 OSGeo4W qgis_app.dll not found

[esnyder-rve]

Describe the bug

I installed both QGIS LTR (3.16.4) and QGIS (3.18.0). QGIS LTR loads fine, whereas QGIS 3.18 does not.

How to Reproduce

1. Completely remove original OSGeo4W
2. Download new OSGeo4W (see https://www.lutraconsulting.co.uk/blog/2021/02/15/qgis-point-cloud-windows/)
3. Advanced Install
4. QGIS & QGIS LTR
5. Error about crssync.exe
   
6. Random request to run a registry file as admin
7. Install done!
8. Run qgis.bat
9. And... Error!
   

QGIS and OS versions
QGIS 3.18.0-5
QGIS LTR 3.16.4-4
Windows 10

Additional context
I looked at qgis-bin.env files and found nothing out of the ordinary when comparing it to qgis-ltr-bin.env.

[esnyder-rve]

I was looking at #41685, but I don't have an MD5 sum issue with any of the packages.

[esnyder-rve]

I found the problem, pdal is not classified as a dependency for 3.18. Installing pdal manually through the advanced installer makes QGIS 3.18 load.

[roya0045]

I think @jef-n did some recent changes. Not sure if this is already fixed or not though.

[esnyder-rve]

Just to throw this in there, once I got 3.18 to load, las & laz files are not supported despite following the instructions and reading the troubleshooting section from Lutra's Guide

[agiudiceandrea]

@esnyder-rve I think it may be worthwhile to create a bug report on https://trac.osgeo.org/osgeo4w/.
Anyway, in the Lutra Consulting guide is stated that you need to "Select the Advanced install and pick qgis-dev from the list of packages".
So, for the moment you should install "qgis-dev", not "qgis", in order to use QGIS with Point Clouds on Windows.

[esnyder-rve]

@agiudiceandrea

So, for the moment you should install "qgis-dev", not "qgis", in order to use QGIS with Point Clouds on Windows.

Thanks, I thought that it was in dev until the actual 3.18 release.

[roya0045]

If the issue persist you can use dependency walker/dependency.exe to check the missing dependencies of qgis dll and place them in the folder. I always need to do this when compiling on windows...

[jef-n]

If the issue persist you can use dependency walker/dependency.exe to check the missing dependencies of qgis dll and place them in the folder. I always need to do this when compiling on windows...

#26891 (comment)

[CoachGD]

I have a similar error message for the Standalone ltr (see below).

Any assistance?

(Note I understand very little of what is being discussed here, so apologies in advance).

I have already tried some the beginning steps of the dependency walker thread extracting the dependancy walker to the C:\Program Files\QGIS 3.16\bin however, I have very little idea what I am actually doing here and reach this point before getting the following error.

I have just had a chat with a friend who has exactly the same issue, so is it a problem with windows or the installer (or both?)

[roya0045]

@jef-n there is also https://github.com/lucasg/Dependencies as dependency walker may become unusable eventually.

@CoachGD inspect the qgs .dll files, and the exe. Bat is just a command file it has no linked dependencies.

[jef-n]

I have already tried some the beginning steps of the dependency walker thread extracting the dependancy walker to the C:\Program Files\QGIS 3.16\bin however, I have very little idea what I am actually doing here and reach this point before getting the following error.

You trying dependency walker on the batch file instead of a exe or dll. Just follow the #26891 (comment)

[jef-n]

@jef-n there is also https://github.com/lucasg/Dependencies as dependency walker may become unusable eventually.

and ldd(1) ;)

[CoachGD]

@CoachGD inspect the qgs .dll files, and the exe. Bat is just a command file it has no linked dependencies.

I have attempted to check a number of dll and exe's and the dependency walker just becomes unresponsive.

[agiudiceandrea]

@CoachGD why don't you try to follow the advise of Jürgen Fischer and follow the instruction at #26891 (comment) ?

[CoachGD]

@CoachGD why don't you try to follow the advise of Jürgen Fischer and follow the instruction at #26891 (comment) ?

I have also tried this and I have the log, however I am none the wiser.

I can load QGIS from the qgis-ltr.bat, however I have never had to do this previously hence my question about whether its an issue with the installer or my OS.

[jef-n]

@CoachGD where's the log?

[CoachGD]

Apologies, see here.

qgis_app.log

[esnyder-rve]

@roya0045 Installing PDAL manually in OSGeo4W solved the problem.

It appears this issue got a little de-railed.
The original problem that this issue was raised for was that pdal is required for QGIS 3.18, but not listed as a dependency in OSGeo4W, and is not installed as such. In order to get QGIS 3.18 to run with OSGeo4W, PDAL must manually be selected to be installed.

[alexbruy]

As far as I can see, PDAL is a dependency now and after installation of latest versions everything works fine.

[cnkant]

I encountered the same issue when I tried to run QGIS versions 3.16, 3.22, and 3.28. Even after reinstalling the program using OSGeo4W, I kept getting an error message saying that OpenCL.dll was missing. Before encountering this problem, I had removed my NVIDIA graphics card from the device and uninstalled its drivers. So, I suspected that the issue might be related to the graphics card driver. Currently, my computer is using the integrated graphics card of an Intel CPU. I reinstalled its driver, and the problem was resolved.