Four of my Github repositories get an "invalid path" error when I try to commit to master on Github Desktop (Windows). They've been working for years. I have copied the folders to and from a laptop recently, but I have also done that in the past with no problems.
error: invalid path 'qbug/'
error: qbug/: cannot add to the index - missing --add option?
fatal: Unable to process path qbug/
How can I fix this, and how can I prevent it from happening in the future?