This question already has an answer here:
I got below error after rebooting one of my production SQL server 2012 enterprise,
The log scan number (151082:691:0) passed to log scan in database 'master' is not valid. This error may indicate data corruption or that the log file (.ldf) does not match the data file (.mdf). If this error occurred during replication, re-create the publication. Otherwise, restore from backup if the problem results in a failure during startup.
This seems master database is corrupted, the SQL server service is not starting, I have latest full back of master, where do I restore master when sql service is not running and can I start sql server in single user mode on same server when master corrupt? If I restore master what will happen to user dbs? is there any difference in restoring master and re-installing sql server?
Very much appreciate your replies.