Hi, after several hours of trying, I'm able to short my bug report to this: I have 3 Computers, Two Linux (Raspbian/Debian, Ubuntu), One Mac (Mavericks). The Debian and the Mac uses Sync 2.0, the Ubuntu computer uses Sync 1.4. 1. When I add a 1.4-style read-write key to my mac, my key is one character too short (32 characters). Adding a space solves this, so I can add the folder. The key was once created with an older version of sync. It has no A,B or R in front of it. 2. Although it was a read-write key, the folder will be treated as a read-only folder. It only offers/shows me the RO key and it does sync the way a read-only folder does. It seems like it "forgets" the RW key. 3. There is no read-only-icon shown for this folder within the application. It is shown in the finder (file explorer), though. note: The folder is not already available in my 2.0 identity in a read-only way. I have no fix for 2 and 3. I'm going to log this now and send a mail to the support, but I thought this deserves a thead here.