The file BK2 is a system file. This file is called Windows Indexing Service Data File. The utility of this file is to construt an indexed catalogue and help in quick searching. The indexing service can be of text information or any kind of file properties. The indexing also supports multilingual features. It merges all the collected information about file in a catalogue which can be used later. The catalogue contains a master index file. This format is produced by Microsoft.
These files are also supported by Windows 7 and 8. This system files indexes information for performing system searches for files. it is often created in a folder C:/System Volume Information/catalog.wci which is basically used to perform file system search and storing data.
In addition to the problem described above, i.e. the lack of the appropriate application to support the .BK2 file, there may be several reasons that cause problems with opening and operation of the data format:
A quite common problem is the lack of application in the appropriate version. Even if you have an application, with the help of which you should open the .BK2 file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .BK2 file, so download the update and check again.
If you have already installed the appropriate application, and it is the correct version, the file may not open correctly, because the operating system does not have information that this program supports the file. So you need to "show" which program the computer should use. To do this:
It also happens that the file you want to open is corrupt and therefore there is no such possibility. In this situation, you should find its different version, or ask a person from whom you got, to send it again.