Resolved iMessage won't open after downgrading to 10.10.5

[khabboub]

so i installed pb5, and i noticed that privateinternetaccess (the VPN i use) no longer worked, so i downgraded back to yosemite using time machine, and now iMessage will not open. every time i click on it, i get a dialogue box "messages cannot be opened because of a problem". i uploaded a screen shot of the whole message

has this happened to anyone? I'm not sure if i should reinstall pb5 and just suck it up for a while, or if there is a solution to all iMessages.

 

[v1597psh]

Probably because iMessage data base is not backwards compatible. Delete your Messages data base from ~/Library/Messages

 

[khabboub]

so what i ended up doing was erasing Yosemite, and reinstalling it as a fresh copy, and then using the migrate assistant to transfer all my data back to the mac.