Hi, sorry, but my time machine is not on....does that matter? I started to do what you suggest and I got a warning that I might delete important files, which scared me 🙂 I am wondering if my problem has something to do with this quoted below from another thread I found, but I can't figure out how to show the hidden files:
I have no idea why your startup disk is full, but I will relate what happened to mine in the even that it may help you. I happened to notice, after my grandchildren were on my Mac, that they had tried to send a large Photo Booth video file via my email to their Mom's email. The file was too large and as such the "send" failed. A few days later, I started getting the pop-up indicating my "startup disk was full...", and letting me know I should delete some files ASAP. That was odd, in that I have a 500GB hard drive and had never used more than about 1/5th of it in the past. I started reading "full disk" mysterious issue on this Community Board and found many other with a similar issue which related to recovered mail messages. I had no way to see what apps or folders/files were hogging my Hard Drive so after reading some posts, downloaded a freeware program (disk inventory X). This showed me that my Mail Messages were now occupying approx. 395 GB of my Hard Drive. I tried for quite some time to follow the advice of other folks posts and find and delete the offending files. Many posts told me I should downloaad some other freeware apps that would allow me to see "Hidden Files" on my Mac and thus delete the Recovered Message file. I found another Community Post that told me to select the show hidden folders and files in my Finder, but I couldn't see such a choice. Then I found out if you change "All Files..." and instead select "Other" in the finder choices it will indeed show the hidden folders/files and allow you to delete them if you dare. I was able to find the Recovered Message folder in my Mailbox (USER.>Library>Mail>etc. etc. etc. and then delte the file. I now have over 400GB available on my Hard Drive.