If you have more than one user account, these instructions must be carried out as an administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the page that opens.
Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.
Copy the words "Starting standard backup" (without the quotes) on this page and paste into the String Matching text field. Note the timestamp of the last message shown. Clear the text field and scroll back in the log to that time. Post the messages timestamped from then until the end of the backup, or the end of the log if that's not clear.
Post the log text, please, not a screenshot. If there are runs of repeated messages, post only one example of each. Don't post many repetitions of the same message.
Some personal information, such as the names of your files, may be included — edit that out, too, but don’t remove the context.