A Microsoft file hosting and synchronization service.
I had an issue with my OneDrive too. First of all, this OneDrive thing integrated with my PC is a total mess. It doesn´t let me move my "pictures" folder to the oder HDD, because for some reason, it can´t be done (because of OneDrive). Now, my cloud OneDrive folder was full and I did not mind it. OneDrive didn't let me deselect which folders inside my documents to synch for some reason too. Another strange function.
What happend 4 days ago and i just noticed it is that I noticed it synced back my old files.
So, my files were not syncing for 3-4 weeks. And 4 days ago (on Friday) I deleted some larger files that I do not need to allow syncing some excel files I would like to have on my mobile phone synched. A big mistake.
After I done that, OneDrive synced my OLD Excel file from the cloud and REPLACED my more recent saved excel file on my PC. So, all things I changed on that file for 3 weeks went lost. And I can not recover it, because OneDrive just offers me an old file version from few weeks ago.