I use Windows 7. I've been making video projects using MS Windows Movie Maker and Premiere Elements v.10 until recently. On 1/25/17 I downloaded a trial version of Pre v.15, used it for a few days, and then tried to buy a licensed version from Adobe website. Didn't like the options, so went to Staples, bought a CD with Premiere 15 (and Photoshop) on it, and installed & registered it on 1/29/17. A lot of confusion resulted; v 15 couldn't read old prel files created by v10, and vice-versa. Looking at the insides of prel files with Notebook and Emacs, it looks like the prel files created by PRE v10 are in clear ASCII XML, which I can understand. The prel files created by v15 look like gibberish, so they're probably encrypted somehow. I'd like to edit the prel files so that the pointer/s to media files point to their new external location, as I could do easily with the Movie Maker project files. So, 2 Q's: 1) am I right that PRE v15 encodes or encrypts prel files, so it's incompatible with prel files made with earlier versions? 2) Any idea how I can change the contents of v15 prel files to accommodate relocated media files? (and maybe a 3rd: did my history of downloading from Adobe, then installing one I bought from Staples have anything to do with my problems?) - Bill Fisher
Premiere Elements is not backwards compatible. Although some people have been able to read recent version .prels in some newer versions of the program, it's not guaranteed to work and can often result in corruption.
There is definitely no way to open a version 10 project a later version of the program nor is there a way to make the project files compatible.
You'll need to finish a project begun in version 10 in version 10.