Fredelia

Thank you, Yorman, deleted the 2 folders (left the data base entries untouched) and can log-in again, so glad to solve that!

I’ll set this issue as solved, but I can’t analyze where it came from.

The only indicator might be the installation of the plugin “Snitch”, because after we have been logged-out, I received 21 alerts from Sucuri, all of them about the same content:

Subject: Post Update

Login Info:
Time: August 3, 2015 2:01 pm
User: XXX(some mails without given user)XXX

Website Info:
Site: http://xxxxxxxx.de
IP Address: xx.xxx.xx.xxx

Notification:
Snitch (private to published); identifier: 28169; name:

However, feel free to send me a @sucuri Mailadress and I’ll give you an admin access, if you want to analyze on-site.

Thanks again so much!

addendum: WordPress version was 4.2.3 not .4

Thank you, Yorman, for your fast and exhaustive answer!