Why do my pdf underlays disappear when I zoom in?

[Eleanor.smith]

I'm working with multiple pdf underlays (thankfully not overlapping) and drawings lines and hatches over the top. Today though, when I try to zoom in, the underlay vanishes, leaving only the rectangle outline behind. 

What can I do to prevent this or bring it back? Is there a command like regen or attsync that can bring back the pdf so I can accurately trace over it?

[rkmcswain]

Have you seen these similar threads and solutions?

[Eleanor.smith]

I had a good look but none of those options is helpful for my problem.

[pendean]

>>>...Today though...<<<
What changed on your computer? Something did, perhaps a graphics card driver update or a removed or added software?
or did something change with where you store files?

Did you restart your computer yet to see if that cleared the issue?
Post screenshots of your ABOUT and GRAPHICSCONFIG command when you can.

[Eleanor.smith · Accepted solution]

yep, I've restarted my laptop and that seems to have fixed the issue. I guess it was just being temperamental.