Actions that I've done to investigate it:
- Uninstall both Application Catalog roles
- Check SMSPORTALWEBSetup.log and SMSAWEBSVCSetup.log in the Configuration Manager folder to track the uninstall progress
- Install both Application Catalog roles with defaults
- Run %windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe /-i –enable
- Solution from SithaYuvaraj
Looking on MS TechNet I found the following post: SCCM 2012 App Catalog Web Page Error
For me this did the trick:
- Adding SYSTEM and/or Local Service account permissions on the Windows\Temp folder
After that the Application Catalog is running fine again! This permissions are needed to let SYSTEM and/or Local Service write to the folder.
Update 29-2: As mentioned on SithaYuvaraj, If you have IPV6 enabled on the SCCM server you may run into this issue as well. Disabling it (or configure it again) resolves this issue!