M21 File Extension

What is M21 file?

M21 is a file extension commonly associated with MPEG-21 Format files. Files with M21 extension may be used by programs distributed for Mac OS, Windows platform. M21 file format, along with 546 other file formats, belongs to the Video Files category. QuickTime Player supports M21 files and is the most frequently used program to handle such files, yet 1 other tools may also be used. Software named QuickTime Player was created by Apple, Inc.. In order to find more detailed information on the software and M21 files, check the developer’s official website.

Programs which support M21 file extension

The following list contains programs grouped by 2 operating systems that support M21 files. Files with M21 suffix can be copied to any mobile device or system platform, but it may not be possible to open them properly on target system.

How to open file with M21 extension?

There can be multiple causes why you have problems with opening M21 files on given system. Fortunately, most common problems with M21 files can be solved without in-depth IT knowledge, and most importantly, in a matter of minutes. We have prepared a listing of which will help you resolve your problems with M21 files.

Step 1. Get the QuickTime Player

Problems with opening and working with M21 files are most probably having to do with no proper software compatible with M21 files being present on your machine. The solution is straightforward, just download and install QuickTime Player. Above you will find a complete listing of programs that support M21 files, classified according to system platforms for which they are available. One of the most risk-free method of downloading software is using links provided by official distributors. Visit QuickTime Player website and download the installer.

Step 2. Check the version of QuickTime Player and update if needed

If you already have QuickTime Player installed on your systems and M21 files are still not opened properly, check if you have the latest version of the software. It may also happen that software creators by updating their applications add compatibility with other, newer file formats. The reason that QuickTime Player cannot handle files with M21 may be that the software is outdated. The most recent version of QuickTime Player is backward compatible and can handle file formats supported by older versions of the software.

Step 3. Assign QuickTime Player to M21 files

After installing QuickTime Player (the most recent version) make sure that it is set as the default application to open M21 files. The process of associating file formats with default application may differ in details depending on platform, but the basic procedure is very similar.

Change the default application in Windows

• Clicking the M21 with right mouse button will bring a menu from which you should select the Open with option
• Select Choose another app → More apps
• Finally select Look for another app on this PC, point to the folder where QuickTime Player is installed, check the Always use this app to open M21 files box and conform your selection by clicking OK button

Change the default application in Mac OS

• By clicking right mouse button on the selected M21 file open the file menu and choose Information
• Find the Open with option – click the title if its hidden
• Select the appropriate software and save your settings by clicking Change all
• If you followed the previous steps a message should appear: This change will be applied to all files with M21 extension. Next, click the Continue button to finalize the process.

Step 4. Check the M21 for errors

If you followed the instructions form the previous steps yet the issue is still not solved, you should verify the M21 file in question. It is probable that the file is corrupted and thus cannot be accessed.

1. The M21 may be infected with malware – make sure to scan it with an antivirus tool.

If the M21 is indeed infected, it is possible that the malware is blocking it from opening. Immediately scan the file using an antivirus tool or scan the whole system to ensure the whole system is safe. If the M21 file is indeed infected follow the instructions below.

2. Verify that the M21 file’s structure is intact

If you obtained the problematic M21 file from a third party, ask them to supply you with another copy. The file might have been copied erroneously and the data lost integrity, which precludes from accessing the file. When downloading the file with M21 extension from the internet an error may occurred resulting in incomplete file. Try downloading the file again.

3. Ensure that you have appropriate access rights

Sometimes in order to access files user need to have administrative privileges. Log out of your current account and log in to an account with sufficient access privileges. Then open the MPEG-21 Format file.

4. Make sure that the system has sufficient resources to run QuickTime Player

If the systems has insufficient resources to open M21 files, try closing all currently running applications and try again.

5. Ensure that you have the latest drivers and system updates and patches installed

Up-to-date system and drivers not only makes your computer more secure, but also may solve problems with MPEG-21 Format file. It may be the case that the M21 files work properly with updated software that addresses some system bugs.

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