Hello, the file you mentioned is installed by VirusBarrier. Why and how, it is them to answer.
You might want to check the permissions on the file, using terminal
open terminal
write
cd
then
cd "
(that is cd and a space after it then double quotes)
then drag the folder which contains the file over terminal window, this will fill in the path for you, and then just close the double quotes
"
and hit enter
this will change the working directory to the one the file is in
now write
ls -al
this will list the content of the folder, including invisible files
compare the permissions of the .vbt5 with other files, if it differs, run
sudo chmod 755 .vbt5
it will ask you for account password, just type it it (no characters will be visible on the screen) and hit enter.
But it might be that VB will not allow you to tamper with that file. In that case, disable VB, delete the file, and try to encrypt the folder again.
Let me know if you get stuck
you can delete the file from the same terminal window
rm .vbt5
Rgds
Zsolt