GVM1261E Your selections created an empty virtual machine list for backup. This issue might occur because all the selected virtual machines contain unsupported characters in their names. Make sure that you selected virtual machines that do not contain unsupported characters in their names.

Explanation
The following characters are not supported in virtual machine names:   ' : ; * ? , < > / \ | . Virtual machine names that contain these characters are automatically removed from the backup task definition. This removal can cause an empty task definition.
Administrator response
Rename the identified virtual machines to remove unsupported characters from their name. Or, select different virtual machines to back up.