Finder repeatedly crashing due to iCloud Drive?

The Finder is repeatedly and endlessly crashing in primary user account (the user account my iMac automatically boots into). I experienced this for the first time last night after I booted into SAFE Mode, then rebooted normally. (I booted into SAFE Mode only to launch a web design app to see if it would load faster. After that test was done, which only took seconds, I rebooted normally.) When I booted to the Finder (not in SAFE Mode but a regular boot), I then immediately switched to my wife's user and left the machine that way until this morning. This morning I woke the iMac and switched to my user, only to find the Finder was repeatedly crashing.

No crashes in my wife's user account or in SAFE Mode in my or my wife's user account — SAFE Mode works fine. I've read that "Dolly Drive" could cause Finder crashing but I've never installed Dolly-anything, now or in the past. I do use Google Drive, DropBox, Copy, Cloud App services, as well as iCloud Drive.

The relevant part of the Console log, which repeats over and over with each crash is as follows:

Jul 24 07:24:27 iMac.local bird[1121]: created directory has a wrong owner (value: root, expected: XXX)

Jul 24 07:24:27 iMac.local bird[1121]: iCloud Drive is not able to run, please run "Repair Disk Permissions" in "Disk Utility"

Jul 24 07:24:27 iMac.local Finder[1119]: setting error: Error Domain=NSCocoaErrorDomain Code=4099 "Couldn’t communicate with a helper application." (The connection to service named com.apple.bird.token was invalidated from this process.) UserInfo=0x618000072580 {NSDebugDescription=The connection to service named com.apple.bird.token was invalidated from this process.}

Jul 24 07:24:27 iMac.local Finder[1119]: Took 4.15s to get the token

Jul 24 07:24:27 iMac com.apple.xpc.launchd[1] (com.apple.bird[1121]): Service exited with abnormal code: 1

Jul 24 07:24:27 iMac com.apple.xpc.launchd[1] (com.apple.bird): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.

Jul 24 07:24:27 iMac Finder[1119]: assertion failed: 14E46: libxpc.dylib + 62495 [80D68997-17B9-32B6-A5FA-A218216415E5]: 0x89

Jul 24 07:24:32 iMac.local OverlayHelper[1122]: --- Log opened Fri Jul 24 07:24:32 2015 ---

Jul 24 07:24:32 iMac.local OverlayHelper[1122]: --- OverlayHelper ---

Jul 24 07:24:33 iMac.local OverlayLoader[1122]: --- Log opened Fri Jul 24 07:24:33 2015 ---

Jul 24 07:24:33 iMac.local OverlayLoader[1122]: --- OverlayLoader ---

Jul 24 07:24:33 iMac kernel[0]: Data/Stack execution not permitted: Finder[pid 1119] at virtual address 0x1070e3000, protections were read-write

Jul 24 07:24:33 iMac com.apple.xpc.launchd[1] (com.apple.ReportCrash[1123]): Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.ReportCrash

Jul 24 07:24:33 iMac.local diagnosticd[146]: error evaluating process info - pid: 1119, punique: 1119

Jul 24 07:24:33 iMac com.apple.xpc.launchd[1] (com.apple.Finder[1119]): Service exited due to signal: Bus error: 10

Jul 24 07:24:33 iMac.local ReportCrash[1123]: Saved crash report for Finder[1119] version 10.10.5 (10.10.5) to /Users/jdw/Library/Logs/DiagnosticReports/Finder_2015-07-24-072433_iMac.crash

Jul 24 07:24:33 iMac.local ReportCrash[1123]: Removing excessive log: file:///Users/jdw/Library/Logs/DiagnosticReports/Finder_2015-07-24-072110_iMac. crash

Jul 24 07:24:33 iMac.local ReportCrash[1123]: Failed to write crash history to file:///Users/jdw/Library/Application%20Support/CrashReporter/Finder_68EE09F5-E DE0-5AC8-AE03-37F3DCDC1FC2.plist.

The XXX in the first line in the above is my OS X user — the user into which my iMac boots.

I rebooted into the Recovery Disk, ran Repair Permissions and Repair Disk and rebooted. Same problem in my primary user account. Finder crashes over and over. No Finder crashing in my wife's account.

The unusual parts of the above Console Crash Log appear to be lines 1 and 2. What's the deal with "root" vs "XXX"? And what's the deal with iCloud Drive? And what is "com.apple.bird.token"?

Since I cannot use the Finder at all within the User account in question, how do I go about solving this problem?

Thank you.