Hi George,
Open Task Manager (Ctrl + Shift + Esc).
On the processes tab, look for anything related to Acronis or that tishell64 dll, if you find any, then end task on it an then try deleting the file.
Otherwise, click the link below to download a small free utility that does not require installation.
https://docs.microsoft.com/en-us/sysinternals/d...
When the file downloads, unzip it.
Depending on your system, run Autoruns or Autoruns64 as Administrator
In the search box in Autoruns, type acronis
Then, right click any entries found and delete them.
Restart your PC and try deleing the file again.