Image manager not showing...

when a new image anywhere is needed, and you click to add or edit the image, nothing happens.
I have NO add ons and just the default template (I was using an other but switched to default to troubleshoot)
There has been NO server changes and the only change was the opencart version was upgraded to the latest version. Problem was present in previous version and upgrade did nothing to solve this.
I have errors displayed enabled, I have checked the logs and there are NO errors present
I have reuploaded all core files with no luck either.
Any suggestions would be great, keep in mind I run a web hosting company, so I am either overlooking the obvious or this issue is at an advanced level...All the basics have been tried!
My next step will be to save the DB and picts and redo the entire install as a fresh install in a test subdomain seems to work fine ( did to ensure it was not server related)
Thanks

I am using the newest version of opencart so upgrading is not an option, it is also listed above as one of the things I have tried.

Does your hosting enable Rocker Loader? It may make the Image Manager not work properly.

No, I am the host and own the servers my clients are on... that is how I know there were no changes.
Open cart works fine on many other clients domains and it works on this clients account when newly installed in a sub domain.
I also found that if I reinstall from new, test the install it works fine, then, if I import the DB to the new install, the image manager no longer works. so this eliminates plugins and templates... it seems to be something in the DB....

Hi

Did you find a solution for this as I now have the exact same issue

Old, but as a follow up, I found one or more of the images were huge, I removed these and the problem disappeared!