Q I recently upgraded my Mac mini Server to Yosemite. When the installer reported there was only a minute or so to go, the process seemed to hang for over an hour. Thankfully it finally got going again and seems to be working well. What caused it to hang like that?
A This is a strange trait with the Yosemite installation which is the result of it taking special measures with any files that it finds in the hidden /usr/local/bin folder. Among many packages which can get installed there are Ghostscript, TeX, Wireshark, and the Python programming language. For some reason, the Yosemite installer moves all files which it finds in that folder to safekeeping during the installation, then moves them all back when it shows that there is only a short time (typically a minute or so) before completion. If you have many files and folders there, this can take several hours. Do not abort the installation or fiddle with it — just let it run to completion and everything should be fine.
Comments Some users have reported that links and some custom installations of items within /usr/local/bin become broken when they install Yosemite. If you want to work around this, the solution is to move everything out of the folder before installing Yosemite, then move it back later. Apple should have warned us about this before the installation proceeded, and fixed its progress reports to allow for it.