BKP files are backup files of Microsoft SQL Server. These files usually include the backup of an entire database or only the data of an incremental backup. For an incremental backup, you will need to re-play more BKP files in a specific order (for a complete restore).
BKP files are compressed versions of the databases and can not simply be used by renaming them with SQL Server. The creation or rewriting of a BKP file can be done via the query console via SQL commands.
It should also be noted that the BKP files of different server versions are only downwardly compatible. A BKP file of the SQL 2000 Server can be restored in SQL Server2005, but not vice versa.
BKP is a proprietary format and can only be processed with Microsoft SQL Server (also Express).
Most often resolving problems with opening BKP files is very simple. Just install an appropriate program that supports such files. All of the listed programs support BKP files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of BKP files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate BKP files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Program that created original file applications is not on the list, select "Browse" option in order to manually locate the directory where Program that created original file has been installed.
Sometimes problems with opening BKP files may not lie with the application itself, but can arise due to other causes, such as: