Hi,

parallel to our other post we have an error after installing the component via joomla installer. There was following message:

....
Unable to backup the core joomla files!
Error: Backup failed

A backup directory 'D:\xampp\htdocs\XXXX\administrator\components\com_multisites\backup_on_install' is created.
This directory contain ALL the joomla core files that will be patched.
The installation of the patches can be performed by using the MultiSites administration.

It seems that is a permission problem

What user does the multisites files have?
What user must the rest of joomla have?

We use a windows server. Therefore I think we cannot upload with FTP layer.

Thanks.

for all other interested in this topic:

We have solved this issue by our own. I think the problem was that we didn't do the patch update directly after installation.

We uninstalled JMS Multisites and reinstalled it. Then we did the patch update directly after. Now there comes the original joomla installation dialog and after that all works well.