2Backup unhandled exception has occurred

I am doing work in Agency where we send our data daily to main branch of Agency. For sending this data we create backup of data and then send it but today I want to create backup but given problem appears due to this problem I can not send data to the main branch agency please provide me its solution I give detail of complete error here.

2Backup
An unhandled exception has occurred in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will be shut down immediately.
Too many files selected. Please select fewer files and try again.
Details Continue Quit
Thanks
