Apple - Can I delete things safely from ~/Library?

To see which folders inside ~/Library use most of the space, run something like

cd ~/Library; du -sm * | sort -rn | head -16

in Terminal which gives you the 16 folders using the most space.

Specific cleanup actions afterwards depend on the folders found.

This question is a bit old now, but I figured I'd add my experience for googling.

While developing BLE applications on 10.11.x versions of Mac OS, I often found that I had to clear BLE data from ~/Library in order to return to a pre-connected/paired state on server (not client) devices.

I began experimenting with ~/Library to reduce bloat on a system where HDD space was running low. Having planned on performing a fresh install anyway, I further experimented by rming the entire ~/Library directory and rebooting. I didn't expect that the system would return to an operational state.

Upon boot I had to log back into iCloud, set up Slack, set preferences on keyboard, trackpad, terminal, browser, programs, etc..

The system survived and is still running great. After all settings were back in place, a df -h showed that I reclaimed about 16GB.

I understand that this could be a hugely risky move depending on what applications are installed and your level of comfort with losing data/time. In my case the user account was not valued and the machine was pending complete format. However, with it being a somewhat loaded dev machine, I was surprised to find that the system was surprisingly tolerant of the complete removal of ~/Library.

~/Library is where all your apps store their prefs, how you want them to work for you.

It would generally be unwise to start playing in there without being certain of what you are doing....

That said, some apps can store large cache files in there, others may be folders for apps you long-since deleted - those would be safe candidates.

70GB is a pretty big lib, btw, mine is only 30GB & I'm a heavy user.

I'd still be very, very careful in there, but maybe try something like Grand Perspective to see what the largest users are. (There's another similar tool I can't right now remember the name of. If someone remembers & drops it in comments, that would be very nice)

Another way to hone down the largest users would be...

• Open the ~/Library folder, set to List View
• Hit Cmd/J for View Options & set to 'Calculate all sizes' [this may take a while]
• Back in the ~/Lib folder, set to sort by Size from the column headers.
• Application Support is usually the largest by quite some margin, so
• Cmd/double click that & repeat the process...