How to Open, Edit, and Convert BC! Files

Usually, BC! files represent incomplete downloads

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 after 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 function similarly to 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 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, or MKV — 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. Some video types, like MP4, will play if the header is complete but the data aren't complete, so skip to the end to see if VLC errors or crashes before concluding that the file is complete.

Adobe Bridge Cache files are used by Adobe Bridge, but they cannot be opened manually by the program because they're automatically created to store metadata.

How to Convert a BC! File

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.