I just updated my installation to the latest release
Zenphoto version 1.4.12 [c1d7e8900b] (Official build)
Since then slideshow has stopped working. Have tried both the slideshow plugins and also changed to released themes rather than my own (which is based on the Zenpage theme). None of these will work with slideshow.
Have I missed something perhaps?

Nothing has been changed on the slideshows unless you have upgraded from a very old version. Are the options set? Is the script enabled to be loaded on the page the slideshow is called? Any errors somewhere? Browser log, server php log?

Upgrade was from 1.4.11
Have just reverted to that release on my dvelopment installation and the slideshow is working again.
Nothing showing in the logs pertaining to slideshow.
Will keep investigating

I can indeed reproduce this. Will investigate as well.

It's related to the new _htaccess file. Reverting to the old _htaccess but with version 1.4.12 brings the slideshow back to life!

Further:

the addition of

RewriteCond %{REQUEST_URI} !(/$|\.)
RewriteRule (.*) %{REQUEST_URI}/ [R=301,L]

is what seems to be causing the problem.

But!

Although reverting to the old _htaccess has displayed the slideshow page there is no "show" - i.e. the slides don't move on automatically. However they do when the "next" control is pressed.

I as well figured it is the trailing slash we have now with all urls. Fix coming soon in the support build.

Thanks!! I'll stop fiddling now!

Fix (by acrylian) is now in the Support build

Sorry for the delay in replying.

Many thanks - that's fixed it.