iMac stuck on white screen and apple logo at startup

Possible Fixes for El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

1. Resetting your Mac’s PRAM and NVRAM
2. Reset the System Management Controller (SMC)
3. Start the computer in Safe Mode, then restart normally. This is slower than a standard startup.
4. Repair the disk by booting the from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
5. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button below Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
6. Install Combo Updater Download 10.12.6 Combo Update and install.
7. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
8. Erase and Install OS X Restart the computer. Immediately after the chime hold down the CommandandRkeys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on Continue button.
2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
4. Set the Format type to Mac OS Extended (Journaled.)
5. Click on the Apply button, then wait for the Done button to activate and click on it.
6. Quit Disk Utility and return to the Utility Menu.
7. Select Reinstall OS X and click on the Continue button.

Did you ever get the problem fixed. I have same issue after installing High Sierra Operating System. I have tried rebooting in Safe Mode, Recovery Mode, First Aid for Disc, but nothing works. The screen is still stuck on White Screen with Apple Logo

Resetting NVRAM could solve the problem

How to reset NVRAM on your Mac - Apple Support

Also try safe mode boot.

Use safe mode to isolate issues with your Mac - Apple Support

Hello. I also have the WSOD. (iMac, 2011, 21.5") High Sierra installed about 2 weeks ago. Worked fine. Then I upgraded FCPX. Not sure if this was a cause, but it was the only upgrade of an app since installing HS. Have attempted the usual remedies (Safe mode, Internet Recovery Mode, PRAM, Disk First Aid, Reload High Sierra (2ce)).

One other series of commands I executed were Terminal Commands. First procedure: Boot with Cmd+S, then enter fsck -fy This checks for file system consistency. The second procedure was: Boot with Cmd+S then enter /sbin/fsck -fy I got the message "Macintosh HD appears to be okay" . Perhaps this suggests my HD is fine, but I am unfamilair with the implications for a next step.

Am now attempting to backup files through Disk Utilities "Restore" command to a Seagate 6TB HD. Once completed, I will attempt to erase the drive, reinstall OS X, and restore files. Pending no change in WSOD, what is a next step? Can I send the iMac for repairs? Would a repair facility know how to spot the problem? (or is the next step full replacement?).

Thanks for any advice!

Hello...Here is an addendum to my efforts to remove the WSOD. Per my recent note, I indicated "I will attempt to erase the drive, reinstall OS X, and restore files". Voil'a...success!

I first transferred my data to an external HD. (I did not use Time Machine, just a straight copy method. If you have Time Machine, this will facilitate later recovery). Once the data was copied, I erased all data on my iMac with Disk Utilities, and reloaded High Sierra. What a surprise when that mountain scenery appeared. I have closed and reopened the computer many times, and all is working well. My dilemma now is that I have not been able to recover some data from my copied files on the external HD. Whereas Time Machine has the appropriate protocols to recover and repopulate the apps, attempting to merely transfer folders will not recover my Sticky notes, or the many folders I created in iMail, or update my contacts. I am now attempting to use Wondershare, but have had limited success. On the other hand, my iMac is working, and I have been able to recover most of the folders from my saved data.

Good luck!

Hello Montana,

What method did you use to transfer the data from the iMac to an external HD? The disk utilities does not allow me to copy from the internal machine to an external drive. I do have a time machine backup file but it is a week old.

Thank you.

Doc,

Here are the steps I followed.

1. Open Disk Utilities

2. In the left pane, click on the name of your external HD (Let's call it "EHD" from here on).

3. From the tabs at the top (e.g., First Aid, Partition, Erase, Restore, Unmount) select Restore

4. You will get a message: "Would you like to restore to "EHD"? The contents of the 'EHD' will be erased and replaced with the data from the volume selected below. Choose the volume you would like to restore to 'EHD'."

5. In the cell/menu below the message select your iMac HD.

6. Click on Restore.

That will initiate the transfer of data.

The term "restore" is misleading, as the data already exists. You will be simply copying it. In essence, you will transfer the data from your iMac to the external hard drive. Remember, any data existing on the EHD will be erased and replaced with your iMac data. To keep things simple on my transfer, I purchased a new external hard drive that was blank. Tip: Format the HD to Mac OS Externded Journaled, before transferring data. I have read that the typical formatting on new HDs are NTSB, a Windows format. Although I was able to transfer my data. I have heard that Time Machine only works on the Mac format.

Good luck...let us know if this works.

Same for me loaded High Sierra. Worked until switched off. Have tried all of above and still stuck. How do I go back to Sierra?

Hard to help when you provide no information. Read Writing an effective Apple Support Communities question. We are not mindreaders.

Same goes for me. Nothing worked even after trying every step carefully.

Option 4 here worked for me - Disk Utility didn't flag any errors though, but upon reboot it took a little longer but my iMac came up just fine. Thanks