Welcome to the Lightroom Community. I'll need more info to help you with this.
What version of Lightroom Classic & the operating system are you working on? Has this started to happen since a recent change on your computer?
Please go to Help > System Info in Lightroom Classic & share the info with us.
Try to reset the GPU caches by following these steps. Please go to the following locations.
- Press the Windows > Enter 'Run' > Type %appdata%\Adobe\CameraRaw > Hit OK
- Rename the GPU folder as 'GPU.old' (add .old at the end)
- Restart Lightroom Classic again.
Let me know how it goes from here.