Mar 14 2019 01:10 AM
What happens if you convert a 100GB E3 mailbox to 2GB F1 mailbox?
what is the best practice in downsizing 100GB E3 mailbox to 2GB F1 mailbox?
Mar 14 2019 07:22 AM
Mar 14 2019 07:44 AM
I agree with Juan!
In fact, it may not work at all and you'll have to reduce the mailbox size to under 2GB beforehand. I'm getting this from here, though it's not an exact match:
Here is Microsoft's advice to "Back up data before switching O365 for business plans" including how to back up the data accordingly.