After updating to Mac OS High Sierra, in the IntelliJ IDEA I got an error:
Can't start Git: /usr/bin/git The path to Git executable is probably not valid.
For this case, I found next solution (run in terminal):
There was a warning:
xcode-select: note: install requested for command line developer tools
After agreeing on UI and receiving “The software was installed.” message, the problem with Git was fixed (of course, after restarting IntelliJ).