Database Restore Msg 3634 Error ’32

I kept getting an odd error message …

Msg 3634, Level 16, State 1, Line 3
The operating system returned the error ’32(The process cannot access the file because it is being used by another process.)’ while attempting ‘RestoreContainer::ValidateTargetForCreation’ on ‘E:\Website.mdf’.
blah blah blah

… while executing this code (simplified) …

RESTORE DATABASE [Website]
FROM DISK = N'E:\backups\Website.bak' WITH FILE = 1,
MOVE N'Website' TO N'D:\Website.mdf',
MOVE N'Website_Indexes' TO N'D:\Website_1.ndf',
MOVE N'Website_Customers' TO N'D:\Website_2.ndf'
MOVE N'Website_log' TO N'D:\Website_3.ldf',
NOUNLOAD, REPLACE, STATS = 1
GO

The solution was to use a double-backslash in the path to the mdf file like so …

RESTORE DATABASE [Website]
FROM DISK = N'E:\\backups\Website.bak' WITH FILE = 1,
MOVE N'Website' TO N'D:\Website.mdf',
MOVE N'Website_Indexes' TO N'D:\Website_1.ndf',
MOVE N'Website_Customers' TO N'D:\Website_2.ndf'
MOVE N'Website_log' TO N'D:\Website_3.ldf',
NOUNLOAD, REPLACE, STATS = 1
GO