How to bypass Adobe's hand-holding and move your disk cache to an external drive

[benwinter]

Under Preferences -> Media & Disk Cache, you have the option of choosing the folder where your disk cache and conformed media will be stored. Unfortunately, Adobe thinks we are hapless teenagers who cannot make good decisions, and if you try to select a location outside of an internal hard drive you will be greeted with the error "The location you have chosen is on an external drive" and be asked to choose again, out of concern for performance.

This is 2021 and there are many external storage options that surpass the performance of internal drives. Or maybe you're like me and have internal M.2 PCIe cards that just happen to be recognized as external drives by fluke of the system drivers. In any case, there is a way around this silliness, and on macOS it's by way of symlinks.

1. Open Terminal and type in ln -s. Don't press enter yet.
2. Drag the folder on your external drive onto Terminal
3. Drag the current directory selected in the AE preferences window onto Terminal (usually /Users/<username>/LIbrary/Application Support/Adobe/Common/Media Cache and similar), then delete it
4. Press enter
5. Terminal will create a symbolic link to your new folder in place of the one After Effects is currently using. AE will be none the wiser.

[Roland Kahlenberg]

I have no issues using an external SSD for my cache drive. Perhaps something else is amiss. I suggest you file a Bug Report and provide as much system information as you can.

[benwinter]

Are you able to change the media conform directories to external? After Effects allows me to change the Media Cache directory but not the directories in the second half of the dialog, the "Conformed Media Cache"

[Roland Kahlenberg]

Yes, I can. No issues. Also, you did mention an issue with your SSDs being recognized at the OS level as an external drive - perhaps this is causing the issue with AE.