Answered
Why won't previous v14 projects load in v14?
My previous premiere elements 14 will not reload, I get the message 'project not compatible with current version'. Any help much appreciated.
Sometimes a work around is the only solution. 
At least you can edit again.
Premiere Elements automatically makes backup copies. You can set the time interval in Preferences. I have mine set to do it more frequently than the default.
Per Bob's suggestion, if you run into a problem you can then create copy of one of the automatic backups and work with that.
Another thing you can do is "Save As". I like to do a Save As "filenameVersion2" or higher number every time I'm trying something new and different.
AdChoices