Windows 10 Upgrade

Hello,

i just upgrade my Dell Latitude E5450 with Windows 8 to Win10.

Everything works, but when i sign in. I can see the Desktop and after 10 sec. Windows shutting down with a bluescreen. Error Message: APC_INDEX_MISMATCH.

How can i fix this issue without reinstalling Windows because there are importent Files on my Device..

Thanks for you help

Chris