From the Backblaze Twitter account:
Worse than we thought @Adobe @creativecloud v. 18.104.22.168 update alpha sorts hidden files on main dir, nukes the top one. Reproducibly.
Just for clarity, it deletes ANY data in the first alpha-sorted hidden directory. Backblaze is just first b/c of “B”.
Absolutely inexcusable. Thankfully, Backblaze have a workaround to avoid it deleting files until Adobe fix this mess.
Update: It gets worse:
[…] The first folder whether hidden or visible (space at the front) by alphabetical sort will have CONTENTS deleted – folder remains.
Update 2: It gets even worse:
Adobe Creative Cloud Deleting Files on Sign In
Update 3: Adobe has reportedly pulled the update and is investigating.