I'm using Flashpaste portable and after I have upgraded to the latest version, all my phrases are gone, and your default phrases are restored. How can I avoid that in the future?
It seems that you copy all files from new version to the your Flashpaste folder include database file, you should copy all files exclude common.db.
But I am sure you can restore your string from Flashpaste build-in backup files.
To avoid this in future, you can open Options -> Database -> and do Copy and switch database, just rename your database to unique name.
On the matter of licence, I constantly change my external storage media from which I launch my portableapps (such as Flashpaste portable) so I am a little bit concerned about the licence. Should I remove my current licence when I plan to make my switch? How can I do that? Will my licence be affected after I have made several switches (although mine is an extended licence)?
No problem, you can use old license at new drive.