MC v15.4 - 0% Finalizing Your Upgrade!

Hello there, well i saw the release of MC 15.4 and wanted to check/test it on my development environment. So i upgraded from the latest 15.3 (15.3.3 - 1065) to the latest 15.4 (15.4 - 4737). configured openjdk run the installer On my first try i wasn't able to get my DS back running. It failed always trying to start the service forthe deployment server. After restoring my snapshot i tried to install it again. Did the same steps. Now the DS was able to start.I was able to easily access the webconsole and everything seemed to work. Then i noticed the notification onthe webconsole that my search services stopped working. So i checked in the admin tool the search service.The admin tool is saying that all my services are OK. I restarted all my services and the server just in case.The admin tool is still showing me that the search service is still fine. So then i thought the config files of the search services are corrupted. So i went to the SOTI folder to renamethe the search folder to search_old and run the installer again to make sure that he configures the search servicenew. That step helped me a lot to fix the search service on many servers. Now i have the problem that i can not login into my webconsole. After the login it gets stuck at an indexing process.See the screenshot below: Any idea how to fix that problem? Or should i restore my snapshot and try to install 15.4 again? EDIT: Tried to uninstall MC 15.4 and reinstall it again. Same result... best regards, Ozan