A Microsoft file hosting and synchronization service.
Finally, seems the latest update has fixed the issue. The app seems to run smoothly. This is good but it cannot change my decision to go away from Microsoft. Until the very last E-mail I dealt with the help desk, the guys kept pointlessly asking for my error logs.
I am familiarizing myself with LibreOffice right now and it is OK. (Well, at least it is free of charge, what else can I say?) In addition to the 1TB space oneDrive offers, I have been subscribing to mega.nz which has 8TB. Since I am going to discontinue my Microsoft subscription, I can use this money to upgrade mega.nz to 16TB, the ROI is far better.
Farewell and RIP Microsoft, I won't miss you.