Yeah, I know there are already lots of threads about this symptom - here are a few that actually look like what I have (as opposed to a hazy green-and-purple look that was often reported a couple years ago):
In my case, as far as I know, nothing was updated between the time it was working fine and now. I'm using PPro CC2019. Windows is at 1903 and claims to be up to date. The last update was last month's patch Tuesday, and I don't even think I rebooted my PC after the last time video was okay. My display adapter is Intel HD Graphics 520, with driver version 22.214.171.12481. I did open Device Manager yesterday to get the model number of the display adapter to ask a totally unrelated question, but I didn't change anything.
After encountering this problem, I first tried rebooting (thinking it was a memory problem). Then after reading many threads, I checked the Mercury Acceleration setting in PPro, but it was already set to "Software Only" (probably to fix some other problem years ago that I no longer remember). I tried switching it to GL, but nothing changed, so I switched it back.
Disabling the display adapter completely does clear up the video. But the system apparently can't drive my big external monitor without it. Editing video on a 13" laptop with no GPU is pretty much a non-starter. (I didn't even try playing any video when it was in that mode - I quickly enabled it again to regain my workspace.) A common solution on other threads is supposedly rolling back to a previous version, but as you can see here, the "Roll Back Driver" button is grayed out in my case!
Suggestions? If I need to downgrade, how do I do it?
We're sorry about the poor experience. We're aware of an issue where newer Intel GPU drivers may cause preview artifacts in Premiere Pro. To solve this please revert to an older version of Intel driver. Please download and install v126.96.36.19990 and check if it's working properly. Let us know if it helps.
Thanks, Sumeet. I'm a little nervous, though (perhaps I just don't know enough about how this stuff works). Two things make me nervous about installing the driver on the page you linked:
If I mess this up, I'm afraid I might not be able to fix it. I googled my version, and even without including the words "Toshiba" or "Intel", just the number "188.8.131.5281" is nowhere on the internet except this thread! If I install the wrong driver, could the whole display fail, preventing me from operating the PC? And how would I know if overwriting the OEM driver will cause me to lose "customized features and solutions to platform-specific issues"?
One thing I didn't mention in my original post is that this is a Japanese Toshiba Dynabook with the Japanese version of Windows (although I switched the interface language to English after I bought it - I'm an American living in Japan). I don't know if this affects the discussion at all, but I thought I should mention it just in case.
Any thoughts on this? I had forgotten about it (busy with other projects) until just now when I tried to use PPro again. I just want a little reassurance that uninstalling my (probably OEM) driver and installing the one Sumeet linked won't risk messing up my PC even worse.
I decided to bravely install the driver you recommended, but when I ran the .exe file, I got the popup shown to the right.
Clicking Yes brings up this page: https://www.intel.com/content/www/us/en/support/articles/000005469/graphics.html
What now? Do I need to contact Japanese Toshiba support?
the "Roll Back Driver" button is grayed out in my case!
Windows doesn't properly update or roll back drivers. Always go right to the device manufacturer's website to download drivers as in the link Sumeet has given you.
I called Toshiba, and they talked me through the wackiest process I've ever seen: Click Start, scroll down to Application Reinstall, right-click and choose "Open file location", right-click on the shortcut file there and choose "Open with... Internet Explorer" (yes, you read that right - modern browsers won't do this) and click through a precise process to reinstall the original driver that came with the PC (which dates 2015).
It does work, but the current version of the driver keeps reinstalling itself when I least expect it, forcing me to go through the process repeatedly (I've done it three times so far). And I'm having other problems in PPro that might be caused by having a 5-year-old driver (masks and crops don't work - nothing becomes transparent) - I've asked about that on a new forum post.