White screen at boot

[zoran]

On my 27" corei7 mid2010 iMac, i get every now and then a white screen, that seems to cover up the users login page. This occurs just before the Apple logo and the Chime sound. Normally when this occurs, thinking that its a freeze, i do a restart by using the power button. But today i acted as if there was no white screen and i pressed the buttons as if i was logging in to my user and it worked. This white screen seemed as if it was a cover up.
What could be wrong? Is there anything i can do about it? Any suggestions?

 

[grwren]

According to Apple Support, https://support.apple.com/en-us/HT210905 , a blank screen (black, grey (is that light gray/whiteish?) or blue) should appear at start up but apparently it shouldn't last too long, I just haven't been able to find out how long. Mine always boots w/white but it usually doesn't last that long, ≈ 15, 30 sec., sometimes a little longer then the logo, progress bar and boot up.

How long does yours last? "But today i acted as if there was no white screen and i pressed the buttons", what buttons did you press? If you think there is a real boot problem maybe you should try following some the steps in the link above or google "white screen at mac boot up" as there are a ton of fixes out there. Good luck!

 

[zoran]

I typed the pass for my user account, and that was it. Apparently the user screen was there, it was just not visible, but i could type, so i did and the pass was entered and i logged in.

 

[grwren]

Well, after doing a bit more web research on this white screen thing I'm starting to think it might be more of an issue than I originally thought. I just assumed that a white screen for a short period at boot, followed by the apple logo, progress bar and boot up were normal. I inherited this imac from my wife last year for as long as I remember always booted this way. White screen, then it boots, never seems to fail, but maybe there is a problem. I'll be going back and doing some of the suggestions from Apple Support plus others I've found on the internet.

 

[zoran]

For my case the whitish screen comes up before the Apple Logo or the Chime!

 

[grwren]

Mine, whitish screen for about 10-15 seconds w/chime, then logo & progress bar & finally desktop, whole thing takes about 90 -100 seconds. I've always assumed this was correct, now I'm not so sure. The Apple Support link says there should be a blank screen, doesn't say for how long and every thing I've googled on this subject seems to imply it could be a potential hardware, software, etc., issue. More research!