These utilities can decompress multiple files and then combine them into a single archive file. Many of these utilities can decompress the file, but only a few can create the files. If you want to combine multiple files back into the RAR format, use WinRAR. In addition, you can merge several files into one file, ZIP, TAR or 7Z archive, if you use the program 7-Zip.
Download WinRAR from the RarLab website and install it. WinRAR is a commercial program, but the web site provides a free trial.
Open WinRAR and select one backup files you want to merge. Click Extract To ("Extract").
Click New Folder ("New folder"). Name the folder and click OK to extract the files.
Repeat these steps to extract other archive files. Specify created in the previous step, a folder to extract each of the files.
Click the Add button ("Add") and select the files in the folder you created. Click OK.
Select the archive location from the drop down menu. Click the button RAR and click OK to create the merged file. You can also use the program 7-Zip to do this, go to the next step.
Download the program 7-Zip website 7-Zip and install it on your computer. 7-Zip is a free program, there are versions for Windows, OSX, Linux and other operating systems.
Place each of the files you want to combine, in a single directory. Depending on the number of items in each archive, placing them in a new folder without any other files will help to simplify the task.
Select the files in the RAR format. Right-click the mouse on the file, select 7-Zip Extract Here"Extract here"). Wait until the extraction.
Press Ctl (or Command on OSX), select all the extracted files. Right-click your mouse on the file, select 7-Zip Add to ("Add"), depending on the type of the archive file that you want to create. Wait for compression. The new merged file will appear in the directory.