I've been using Zenphoto for a year, all was well.
I decided to do the upgrade (I don't know what version I had before - Nov 2013 is earliest date on local files).
When I logged on this time it gave me the message that my password was too short so i changed it.
I see a similar issue here but I'm not a programmer so I don't want to muddy the water:
https://github.com/zenphoto/zenphoto/issues/908

Then I backed up the data using the admin page zenphoto.

I followed the upgrade instructions exactly - deleted the files online, then uploaded the new ones.
I got the error page saying some files needed to be deleted - they seem to have already been updated on my computer but I had to ok this.

Now I have a blank page.
According to the forum this could be permissions so I checked the SQL permissions on my service provider and ran the "Check database" tool - ok

I had backed up my files, but the site/zenphoto/backup files are .zdp files not .sql
I'm not sure where to upload the replacement

I even re-installed into a fresh folder and get another error page asking for database so i created a new one online but can't seem to point to it.
Mac OS X 6.8 Chrome or Firefox

What can I remove to start over without losing all my photo data?
PS I'm not a programmer, and the first time I installed it worked fine. I use godaddy as a host.

You also need to look into your error logs. Not only the Zenphoto one but the server one. Without that we sadly cannot help as we would have to guess.

Also be sure to remove all non official themes as you may very well see an incompatibility with a third party or custom theme. If your old version was from 2013 that might very well happen.

[i]I had backed up my files, but the site/zenphoto/backup files are .zdp files not .sql[/i]
Those are files to be used with Zenphoto's own database backup tool. Of course if ZP is not working that doesn't help now.

Please attache the url to the site in your forum profile so we can at least take a look.

after several days of replacing this and that I got back to an error page with the huge list of files that supposedly needed to be updated.

then I discovered that godaddy had an "Installatron" auto-installer for a number of apps including zenphoto so I held my breath (I had a full site backup including the original zenphoto install folder) and told it to update.

it worked!!!!

I haven't found any server error logs, and I truly did follow upgrade instructions, so I'm relieved to say I dumb-lucked out.
Even godaddy didn't tell me about installatron, so - whew!

Thank you for your reply, and I hope to always have access to installatron!!!

The file list is just a warning as explained here http://www.zenphoto.org/news/installation-and-upgrading

If it works, great. But please note that we don't directly support these one click installers like Installatron. Maybe they work great now but we had lots of issue reports especially on upgrades with these.