I recently downloaded Microsoft Powerpoint on my Mac. I found out that when I edit my presentation it will actually autosave it to cloud, just like the web app. It was working well for a while. But today I closed my window somehow hours of my progress was gone. Turns out that I ran out of the "free 5gb of storage" and I ran out of storage without noticing it, so it did not save. I'm never going for cloud EVER again. We all make mistakes, and this one taught me a lesson not to use cloud storage. BACKUP BACKUP BACKUP GUYS
You're right... I was actually going to hit the offline save button, but it said it's already saved and synced with the cloud, so I thought I was fine. However, it wasn't saved to the cloud due to lack of space in onedrive and they never told me about that.