wrong (older) thumbnail sent by email

We are using a licensed version of NetCam Studio (32bit because we use a USB local attached webcam), running as a service.

My task:
Once a day at a specified time, a picture has to be taken and sent by eMail

My problem:
eMails are sent successfully at the specified time. The created thumbnail in the folder \ProgramData\Moonware\Netcam Studio\Server\Library\Thumbnails has a correct timestamp, but the picture in the mail is definitively not actual (older). For testing purposes, I aligned the camera to a real-time clock with calendar display.

My settings:
Scheduler: record a video each weekday (Mon-Fri), starting at 5pm.
Maximum recording duration: 35 min so that only one video and only one thumbnail are created (the scheduled recording duration is at least 30 min.)
Retention Period for the library: 2 hours in order to assure, that older videos/thumbnails are deleted when sending the next eMail
Active Rule: when “RecordingFinished” then “SendEmail” with “Attach Pictures = True”

Do you have any recommendation how I should configure NetCam Studio to get the correct picture in the email?

I remember something about this … Somewhere in a cache there is a picture, but I am not sure where. I suggest a clean installation.
-start installation program and use Remove.
-go to C:\ProgramData\Moonware\Netcam Studio\Server an delete all.
-go to C:\Users\henrik\AppData\Roaming\Moonware (change henrik to your account) and delete all.
-go to C:\Users\henrik\AppData\Local\Moonware (change henrik to your account) and delete all.
-install Netcam Studio again.