If you have a very large file that was created by using Generate Script (Data Only) via SQL Server Management Studio (SSMS) you will probably not be able to load it in SSMS to run it. The solution is to use the Command Prompt as follows.

sqlcmd -S <Server>\<Instance> -i <Full Path of .sql File> -I

The -I at the end is used when there is Quoted Identifiers, which is just about all the time!

Other Command Line Parameters that might be of use.

Sqlcmd            [-U login id]          [-P password]
  [-S server]            [-H hostname]          [-E trusted connection]
  [-d use database name] [-l login timeout]     [-t query timeout] 
  [-h headers]           [-s colseparator]      [-w screen width]
  [-a packetsize]        [-e echo input]        [-I Enable Quoted Identifiers]
  [-c cmdend]            [-L[c] list servers[clean output]]
  [-q "cmdline query"]   [-Q "cmdline query" and exit] 
  [-m errorlevel]        [-V severitylevel]     [-W remove trailing spaces]
  [-u unicode output]    [-r[0|1] msgs to stderr]
  [-i inputfile]         [-o outputfile]        [-z new password]
  [-f  | i:[,o:]] [-Z new password and exit] 
  [-k[1|2] remove[replace] control characters]
  [-y variable length type display width]
  [-Y fixed length type display width]
  [-p[1] print statistics[colon format]]
  [-R use client regional setting]
  [-b On error batch abort]
  [-v var = "value"...]  [-A dedicated admin connection]
  [-X[1] disable commands, startup script, environment variables [and exit]]
  [-x disable variable substitution]
  [-? show syntax summary]