Hi ​@yakub.karahasanoglu,

Did you try to re-download the ISO? Could be an issue with the ISO or the files within.

And did you make sure that you are using the correct installer? As far as I remember there are two:

One for the upgrade and one for clean installations:

12.2.0.334 to 12.3.1.1139 upgrade failed | Veeam Community Resource Hub

Hard to say ​@yakub.karahasanoglu . You could possibly try to re-download the ISO file from your Support account, or check the install logs:

Installation and upgrade logs - the %ProgramData%\Veeam\Setup\Temp folder

Which one would be better for me to download?

When I checked I didn't see anything useful.

Check the log files here - C:\ProgramData\Veeam\Setup\Temp\

If that does not help check what Lukas posted and worse case contact Support.

You can try the upgrade ISO and see.  If that fails download the full ISO as it will do the same thing.

​@yakub.karahasanoglu - I didn’t see any differing ISO for upgrade vs install. I don’t think there are any. There’s just 1 download I’m pretty sure. If you didn’t see anything in the log, your best bet is to contact Support.

Just to add, also check the Windows Event Logs and see if anything is logged there as well. 

The log created in the temp file during the upgrade is as follows.

SetupBackupServer_16_04_2025_17_21_16.txt

[16.04.2025 17:18:38]:[00000001] [veeam] INFO    Checking installed product version (Id='{B1E61D9B-8D78-4419-8F63-D21279F71A56}', Name='Backup', ProductVersion=12.3.0.310, IsPreview=False)
/16.04.2025 17:18:38]:]00000001] ]VEEAM] INFO    Analysing installed product (Version='12.2.0.334')

If I uninstall the application and install the new version, can I get the jobs back from the backup configuration? Or will I have any problems?

​@yakub.karahasanoglu - yeah...not much there. I advise getting with Support to help with the Upgrde. Assuming you met all the requirements for Upgrade?...Support is your best avenue to get you sorted.