Symptom

Backing up databases/schemas is sometimes problematic when using the MySQL Workbench GUI. A recent example included the metadatablobvalues table being bigger than the max_allowed_packet setting in Workbench. 

This is in fact a bug in Workbench, in that the max_allowed_packet setting in the my.ini file is being ignored by the data export GUI. 

Resolution

To get around issues such as this, you can run a backup using Command Prompt. Simply search for "cmd" in windows and be sure to run the Command Prompt as administrator. Then follow the following steps:

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C:\Windows\system32>cd..
C:\Windows>cd..
C:\>cd program files
C:\Program Files>cd mysql
C:\Program Files\MySQL>cd mysql server 5.7
C:\Program Files\MySQL\MySQL Server 5.7>cd bin
C:\Program Files\MySQL\MySQL Server 5.7\bin>mysqldump.exe --single-transaction --routines --triggers --hex-blob --compress --opt --default-character-set=utf8mb4 --max_allowed_packet=1024M --password=ROOT/MYSQL USER PASSWORD HERE   --user=MYSQL USER HERE --host=localhost --protocol=tcp --port=3306 --databases -r d:\temp\curatordb.sql  curatordb
mysqldump: [Warning] Using a password on the command line interface can be insecure.
C:\Program Files\MySQL\MySQL Server 5.7\bin>
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Note: In the above example the restore location is set to d:\temp but you can replace that with your specified restore location. curatordb is being restored in the example. Be sure to change directory to your mysqldump.exe location if it's different to the above.