Apple - quicklookd and revisiond eating my CPU

This is how I fixed this problem. It might help you but from what I've seen so far, even thought there are similar issues, the source of problems are different.

I've ran sudo iosnoop -n quicklookd - it shown something like this:

  UID   PID D    BLOCK   SIZE       COMM PATHNAME
  501  5656 W 56385320  32768 quicklookd ??/Quick Look/cloudthumbnails.db-journal
  501  5656 W 56385320   4096 quicklookd ??/Quick Look/cloudthumbnails.db-journal
  501  5656 W 48100696  12288 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 48100816   8192 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 48100840   8192 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 56385640  28672 quicklookd ??/T/etilqs_kYNR5XinU71bydh
  501  5656 W 56386736  32768 quicklookd ??/Quick Look/cloudthumbnails.db-journal
  501  5656 W 56386736   4096 quicklookd ??/Quick Look/cloudthumbnails.db-journal
  501  5656 W 48100696  12288 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 48100816   8192 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 48100840   8192 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 56387280  28672 quicklookd ??/T/etilqs_ejadCww3DunYuu3
  501  5656 W 56474504  32768 quicklookd ??/Quick Look/cloudthumbnails.db-journal
  501  5656 W 56474504   4096 quicklookd ??/Quick Look/cloudthumbnails.db-journal
  501  5656 W 48100696  12288 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 48100816   8192 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 48100840   8192 quicklookd ??/Quick Look/cloudthumbnails.db
  501  5656 W 56474568  28672 quicklookd ??/T/etilqs_QzHS30kC4YT8ETi

I gave it a shot and looked for cloudthumbnails.db file. Bingo! Found it in /Users/me/Library/Application Support/Quick Look and the quicklookd was writing to cloudthumbnails.db-journal like crazy. But it was writing small chunks, then deleting the file and writing those small chunks again. Unfortunately this is a binary file, so it's not easy to read, but I gave it a shot and just did tail cloudthumbnails.db-journal. I got mostly gibberish, but I noticed repeated path /Users/me/Library/Mobile Documents/com~apple~CloudDocs/ and some files there.

This is iCloud folder and for some reason quicklookd was unable to process those files. I deleted them (moved to trash and emptied) and TADA! It solved the problem.

I have no idea why this happened, why quicklookd was unable to process those files. I've sent those files again to iCloud and everything was fine - no crazy behavior of quicklookd.

I would try using opensnoop to see what files quicklookd is looking at. There might be a particular files that it is either having trouble reading or writing to.

While they are using excessive CPU, open a Terminal window and type the following command. You'll be prompted for your password.

 sudo opensnoop -n quicklookd

This should show you all the files that quicklookd is reading or writing to, and might help you identify if one particular file or folder of files is causing the issue.

Try the same thing for revisiond.

I couldn't figure out how to log in to Terminal, so I just killed quicklookd, which was hogging so much memory that nothing else would run. Instant relief! I suppose it will start up again once I reboot, though.