I'm facing same issue, is there any solution?
Because of this backup certificate error, I get below error when I restore
RepositorySnapshotManager.exe -restore -path=C:\Setup\backup -installer=C:\Setup -supportingContentLocation=C:\Setup\Additional -databasePassword=pass
Exception in thread main, msg=Could not find file 'C:\Setup\backup\Certificate\client.pfx'., code=-2147024894
I faced this same issue today and have the following point to help in the future...
You need to run the RSM backup when logged in as the same user that runs the QS services in order to capture the client.pfx .
If you run it as a regular admin then the restore procedure will fail to find client.pfx.
This is because the Current user > Personal cert will not be accessible unless executed as the service account.
To work around this you can follow the online QS help for v3.0 onwards which details how to manually backup and restore the certificates.
You should be able to manually backup the client certificate and store this in your backup folder, for the restore process to then find and use later.
Make sure you have a copy of the folder 'C:\Program Files\Qlik\Sense\Repository\Util\RepositorySnapshotManager' stored in your backup folder.
When doing the full restore the RSM will delete the existing QS installation and folders, including the above location, so if you are running the RSM from the default location the process will fail.