How to proceed?

Hy,

I have the new fortnite update 8.10 installed to play again. Everything had worked without problems before the update. After the update, I wanted to start fortnite and then came this window on my screen… I had only made the update otherwise nothing. Can someone help me? Or, the problem still someone after the update and could solve it?

I had already uninstalled Fortnite, uninstalled Epig Games launcher and even rebuilt the PC and made sure to leave no rest data from fortnite in folders

gone down, which I overlooked to clear.

Seems to be on your Windows itself. Even if the GTA V concerns this also seems to be the cause of your problems regarding Fortnite:
https://support.rockstargames.com/de/articles/204933118/Wie-man-bei-GTAV-PC-Dependency-MFREADWRITE-DLL-is-missing-Please-reinstall-the-game-Fehlermeldungen-behebt

Here you can read, or download the .dll file:

https://www.solvusoft.com/de/files/fehlend-wurde-nicht-gefunden-fehler/dll/windows/microsoft/windows-7-home-premium/mfreadwrite-dll/

If it still does not work, just reinstall the program. The old version but once suaber uninstall and shut down between PC and start again.

With CCleaner (https://www.pcwelt.de/downloads/Cleaning-Tool-CCleaner-556951.html you can also clean the registry before you reinstall the program.