File with 001 extension are known as split archive file. This file format is created by compression or archive software application.
The main purpose of this file is to split the data to be compressed or archived in case the data size of the files increases a specified limit. In this case the archive software application creates a number of split archive files which can hold the size of the data to be archived. The extension used for the first file in this case is 001 and the extensions are given in progressive order to the next files in the series.
In addition to the problem described above, i.e. the lack of the appropriate application to support the .001 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 .001 file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .001 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.