If you are dealing with a large scripted databases and having difficulty restoring it with SSMS, follow the instructions below.

Open the Sql Command Prompt and execute the following: Replace the braces with your settings.

sqlcmd -S {SQL-INSTANCE-NAME} -i {PATH-TO-SCRIPT} -o {LOG-FILE} -U {LOGIN-USERNAME} -P "{LOGIN-PASSWORD}" -d {RESTORE-DATABASE-NAME}

Safety tip:
 Ensure each query is followed by an SQL "GO" for optimal performance and to reduce the chance of out of memory errors.