Black screen & reboot after exiting game on steam for my imac pro (vega 64)

[gerrard0804]

Having been running games on windows 10 bootcamp，it returns to my desktop after exiting game until installing the latest windows updates last night.

It just shows a black screen for 10 seconds then rebooting itself. I tried two games on steam having the same situation while both game run normally.

Tried reinstall the latest from bootcampdrivers(Nov19 version), it gets the same result.

My configs as below:
-iMac Pro(2017) with vega 64
- bootcamp driver from bootcampdrivers(Nov19 version)
- windows 10 bootcamp (latest system updates until 30 Nov 19)

 

[DLary]

Did you try deleting and re installing Steam?

 

[gerrard0804]

Did you try deleting and re installing Steam?

Did you try deleting and re installing Steam?

tried deleting all folders and files (except steamapp folder and steam.exe) under program file and clicked on steam.exe to reinstall all itself, but still rebooted windows instead of back to desktop after exiting game
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I tried forza 4 demo, it reverted to desktop normally, so there must be something to do with steam games?