my screen turns Pink for a short time during start-up

William try a PRAM reset.

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Option, Command (⌘), P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on your Mac.
4. Immediately press and hold the Option-Command-P-R keys. You must press this key combination before the gray screen appears. Continue holding the keys down until your Mac restarts, and you hear the startup sound for the second time.
5. Release the keys.

Resetting PRAM may change some system settings and preferences. Use System Preferences to restore your settings.

Also check thru this trouble shooting procedure.

Apple computers: Troubleshooting issues with video on internal or external displays

co-creator,

I ma having the same problem. I have a late 2012 Mac Mini running the latest release of Yosemite with Viewsonic VX2453mh monitor. This happens to me when the screen saver kicks in. Having done a search on this issue, it appears that we do not have to worry that either of our displays is bad. That is the good news. The bad news is that I have not found a solution. This does appear to an issue on both Mavericks and Yosemite. For me it happened after I put some pictures in Macintosh HD/Library/Desktop Pictures, but I think this is just a coincidence.

Thank you Sanjampet. Your suggestion worked for my issue! I wanted to give it about a day just to be sure.

Glad it helped🙂