When a master browser fails, a backup browser detects the failure within 15 minutes and forces an election of a new master browser.
If a client performs its browse request (using the NetServerEnum API call) after a master browser fails but before a backup browser detects the failure, the client forces an election. If a master browser fails and there are no backup browsers, browsing in the workgroup or domain will not function correctly.
During the gap between the master browser's failure and the election of a new master browser, the workgroup or domain can disappear from the lists that are visible to computers in other workgroups and domains.