Sometimes when you open a record, a message will appear saying, 'The Record is locked and is available for viewing only'. This means that another user in the system has the record open.
If you are attempting to bring a Browse List of records up into a data entry window, you may get the same message. In this instance, the message is referring to the first record in the list.
If you only want to view the record, say 'Yes' to the pop up, and proceed to view the record.
If you want to edit the record, you will need to wait for the other user to close the record. Close the record, and re-open it later on.