How to Open, Edit, and Convert BC! Files

Screenshot of several BC! files in Windows 10
BC! Files.

A file with the BC! file extension is a BitComet or BitLord Incomplete Download file. An incomplete file is just a partial file that the torrent program hasn't yet finished downloading.

During the download process, the program appends the BC! file extension to all files, and then renames them to their proper extensions once they've finished downloading. You'll only see a BC! file if you're watching the file as it downloads or if something (you, the program, or the connection) stopped the download from completing.

BC! files are kind of like CRDOWNLOAD files used by the Chrome web browser and XXXXXX files produced by allTunes, both of which are partial/incomplete download files.

Some BC! or BC files may instead be Adobe Bridge Cache files that store image information used by Adobe Bridge.

How to Open a BC! File

Most BC! files can't be opened by any program because the file is only partially valid. However, if you're sure that the file is completely downloaded, but for some reason the BC! extension is still attached to the file name, you could try manually renaming the file to the appropriate extension. While not common, it's possible BitLord or BitComet had some kind of error and didn't complete that last step automatically.

For example, if it's an MP4 video file you're downloading, and the whole file appears to be saved to your computer and isn't downloading any longer, just rename the file from whatever.BC! to whatever.MP4.

Renaming the file in this way might only be possible if you close down the program that downloaded it. For example, if BitLord makes the BC! file and you're trying to rename it to use the .MP4 extension, close out of BitLord first so that it's not using the file anymore, and then rename the file.

Something else you can do if you know the BC! file is a fully downloaded media file, but you're not sure what extension it should have - like an MP3, AVI, WAV, MKV, etc., is to just drag and drop the BC! file into VLC. If the file is complete (has a complete header and a full set of data), VLC should play it.

Adobe Bridge Cache files are used by Adobe Bridge, but it's unlikely that they can actually be opened manually by the program since they're automatically created and are just used to store metadata.

How to Convert a BC! File

As explained above, BC! files usually aren't complete, usable files. If you have a BC! file that hasn't finished downloading, and therefore can't open properly without the rest of the file, then you certainly can't convert it to some other format either.

However, if the file does manage to work properly after renaming the file extension to something else, you can then, of course, treat the file like you would any other and use a free file converter to save it to whatever different format you need the file in.

For example, continuing the example several paragraphs above, if you rename a BC! file to an MP4 file, and then find that it plays normally, you can convert it using any free video converter.