若要还原 master 数据库，服务器必须以单用户模式运行。有关在单用户模式下启动的信息，请参阅联机丛书中的"如何启动 SQL Server 实例"。
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English version
To restore the master database, the server must be running in single-user mode. For information on starting in single-user mode, see "How to: Start an Instance of SQL Server (sqlservr.exe)" in Books Online.
SQL Server