Backup Error on all my 3 Installations 2014 Premium

Hi.
I use the 2014 Premium and since a while the Software failed after backup on all my 3 PC. Win7 and WIN 8.1.
Arconis creates the file on a harddisk (Image C: to D:\image or also Image C to C:\image or Image C to a NAS).
When the Software tries to compare the file an error occurs.
Error open backup c:\image\myimage.tib failed.
I checked the Image, and I could Mount the file and copy files. (with the Acronis tool Mount Image)

2014 the Software was running without error on 3 PC.
2015 the Software failed on 3 differnt PC. (Still the same Task running without modifications).

Is it necessary to buy the upgrade every year?

regards
Bernd

Mehr Informationen über diesen Fehler und mögliche Lösungen können online in der Acronis Knowledge Base verfügbar sein. Um auf die Online-Ressource manuell zugreifen zu können, geben Sie den Ereignis-Code hier ein: http://kb.acronis.com/errorcode/
Ereignis-Code: 0x01E50015+0x01E5001A+0x000B041D+0x00040011+0x0000FFF0+0x80070002