Q: iCloud password request at startup or restart

It APPEARS that I've fixed it, though the process and ultimate outcome doesn't give confidence that it won't reappear.

First, important to note that this problem appeared with the update to OS X version 10.9.4. It happened on both of our Macs: MacBook Pro and iMac 27". On the iMac, I noticed after the fix that it happened only on my account, and not on my wife's. That was a clue, if I'd realized it earlier.

Second, the dialog box didn't appear until long after powering up or commanding restart.

Third, the dialog box appeared AFTER the Google Drive access was complete. Ultimately, this was THE clue, but had nothing to do with Google Drive.

I looked into both suggestions that were made, before stumbling across the (apparent) solution. The computer name was consistent in the places it appears. I looked into a Keychain Reset, but was put off by Apple's Help dialogue, notably failure to state up front how to recover the 'put aside' Keychain data.

When the problem first appeared, I went immediately to the iCloud Preferences and unchecked the Keychain; no joy. Also checked the Start Up Items in my User Preferences. That's always a source of this kind of issue (stuff happening after start up), but again nothing was obvious.

The delay until after Google Drive startup made me think perhaps something was set to try to synchronize data between Google Drive and iCloud, but I couldn't find anything. Nor was there anything in either 'drive' that I would want to share between them.

However, it became clear that the iCloud post-restart process probably was the culprit. Recall that I'd already unchecked the Keychain sync item. So, looking through the list of iCloud sync items, it appeared to me that the most likely troublemakers would be the Back To My Mac and Find My Mac items (I may have those names slightly wrong, but you'll know them when you see them).

I unchecked both items, and, PROBLEM GONE.

I then proceeded to restore the 'checkmark' on each one to see which was the troublemaker: PROBLEM WOULD NOT RETURN!

I even rechecked the Keychain item, but problem was gone ... hopefully for good.

PS: Unchecking and rechecking the Keychain item resurrects the secret handshake for enabling the Keychain access via iCloud. Hopefully you saved the secret code and still have the phone number you gave it during the setup and can get text messages on the phone. Fortunately, I did, but it still was a little spooky because all that was deep in my memory dustbin.

Bottom line is that (my best guess) something was done in the setup of Find My Mac item in iCloud Preference pane (again, my best guess as to the real culprit, because of how long it takes before the offending dialogue box appears). It was either that or the Back To My Mac item ... or both? So, just uncheck them, assuming they're checked, do a Restart (just in case it's sequence dependent) and then restore the checkmark (or not if you don't want to), and the puzzling dialogue box should no longer appear ... at least until Apple fumbles the ball in some other way.

Cheers,

-bcd