[osgeo4w-dev] [osgeo4w] #804: Could not load qgis_app.dll - QGIS LTR 3.28.11 OSGeo4W Installer

[OSGeo4W]

#804: Could not load qgis_app.dll - QGIS LTR 3.28.11 OSGeo4W Installer
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Reporter:  ascottwwf                            |       Owner:  osgeo4w-
                                                |  dev@…
    Type:  defect                               |      Status:  new
Priority:  normal                               |   Component:  Installer
 Version:  1.0                                  |  Resolution:
Keywords:  QGIS LTR OSGeo4W scripted installer  |
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Comment (by ascottwwf):

 I've solved it! - (embarressed face) \\\\
 What I failed to mention in the thread above is we use the Powershell App
 Deploy Toolkit (or PSADT) https://psappdeploytoolkit.com/ to wrap the
 installer. This is so we can install as system while giving the user
 visibility of the dialogs and a prompt to close the QGIS application if it
 is running when the install lands on their machine (we also use this so
 they have the opportunity to defer the install until later).\\
 But as part of the PSADT install I had set it to block the execution of
 the QGIS executable "qgis-ltr-bin.exe" (or processname "qgis-ltr-bin"),
 which in itself is usually a good thing - to prevent them opening the app
 while the install is still in progress.\\\\
 I think this was the cause of the problem, As during the OSGeo4W install
 the "qgis-ltr-bin" processname was being launched (or one by the same
 name) and this process was being blocked - causing the install to not
 entirely succeed.\\\\
 So my fix was to remove the PSADT -BlockExecution switch and the install
 now succeeds
 Obviously (and unfortunately) we can't prevent our (impatient) users from
 relaunching the QGIS app before it has completed the install, but at least
 if they wait the install now completes without issue.\\\\
 Sorry for wasting your time, although hopefully this thread may aid
 someone else with similar issues in the future.
-- 
Ticket URL: <https://trac.osgeo.org/osgeo4w/ticket/804#comment:15>
OSGeo4W <http://trac.osgeo.org/osgeo4w>
OSGeo4W is the Windows installer and package environment for the OSGeo stack.