Windows MySQL 5.5 Cannot connect to localhost: ERROR 1130 (HY000): Host 'localhost' is not allowed to connect to this MySQL server
Short answer: I recovered from backup

During my work day, I do perform several mysqldumps of my work database and mysql. But I could not perform an import since it would fail with the same Error 1130.

I stopped the db, I moved my data/mysql directory out of the way, and then dropped in my March 1st data/mysql. I restarted the database and found I could connect and perform selects from within MySQL Workbench and the DOS command line.

I performed a reboot, restarted the database, and all good.

My backup batch file (copied below) performs a dump of my work database (wipdb) to wipdb.sql and mysql database to mysql.sql

Note the WinRAR command contains the word "PASSWORD" which is the plaintext password used to encrypt my backups. If you use the script, you might want to change it to something else...

The WinRAR files are saved to C:\Backups\Daily\BackupYYYYMMDD-XX.rar where YYYYMMDD is the date and XX is numeric incremented during ever iteration of the script during the day

PATH=%PATH%;C:\Progra~1\WinRar

call mysqldump.exe wipdb --single-transaction --default-character-set=utf8 --max_allowed_packet=1G --user=root &gt; C:\Backups\Daily\wipdb.sql

call mysqldump.exe mysql --single-transaction --default-character-set=utf8 --max_allowed_packet=1G --user=root &gt; C:\Backups\Daily\mysql.sql

cd C:\backups

rar.exe a C:\Backups\Daily\Backup.rar -pPASSWORD -ai -mt2 -m4 -t -agYYYYMMDD-NN -dh -ed -idcdp -r C:\Tools\ C:\Data\websites\  C:\Progra~2\Zend\*.conf C:\Progra~2\Zend\MySQL55\data\mysql C:\Progra~2\Zend\MySQL55\data\wipdb C:\Progra~2\Zend\*.ini C:\Windows\System32\drivers\etc\* C:\Backups\Keep\* C:\Backup\Daily\*.sql