MUL file icon

MUL File Extension

Ultima Online Multi Format
  • Developer
    Origin Systems
  • Category
  • Popularity
    3.3 (3 votes)

What is MUL file?

MUL is a file extension commonly associated with Ultima Online Multi Format files. Ultima Online Multi Format format was developed by Origin Systems. MUL files are supported by software applications available for devices running Windows. MUL file belongs to the Game Files category just like 1509 other filename extensions listed in our database. MULTool supports MUL files and is the most frequently used program to handle such files, yet 2 other tools may also be used.

Programs which support MUL file extension

Below is a table that list programs that support MUL files. MUL files can be encountered on all system platforms, including mobile, yet there is no guarantee each will properly support such files.

Programs that support MUL file

How to open file with MUL extension?

There can be multiple causes why you have problems with opening MUL files on given system. What is important, all common issues related to files with MUL extension can be resolved by the users themselves. The process is quick and doesn’t involve an IT expert. The list below will guide you through the process of addressing the encountered problem.

Step 1. Get the MULTool

Install software to open MUL file The most common reason for such problems is the lack of proper applications that supports MUL files installed on the system. The most obvious solution is to download and install MULTool or one to the listed programs: MulPatcher, Ultima Online. On the top of the page a list that contains all programs grouped based on operating systems supported can be found. One of the most risk-free method of downloading software is using links provided by official distributors. Visit MULTool website and download the installer.

Step 2. Update MULTool to the latest version

Update software that support file extension MULIf the problems with opening MUL files still occur even after installing MULTool, it is possible that you have an outdated version of the software. Check the developer’s website whether a newer version of MULTool is available. Sometimes software developers introduce new formats in place of that already supports along with newer versions of their applications. The reason that MULTool cannot handle files with MUL may be that the software is outdated. All of the file formats that were handled just fine by the previous versions of given program should be also possible to open using MULTool.

Step 3. Associate Ultima Online Multi Format files with MULTool

If you have the latest version of MULTool installed and the problem persists, select it as the default program to be used to manage MUL on your device. The process of associating file formats with default application may differ in details depending on platform, but the basic procedure is very similar.

Associate software with MUL file on Windows

The procedure to change the default program in Windows

  • Clicking the MUL with right mouse button will bring a menu from which you should select the Open with option
  • Next, select the Choose another app option and then using More apps open the list of available applications
  • Finally select Look for another app on this PC, point to the folder where MULTool is installed, check the Always use this app to open MUL files box and conform your selection by clicking OK button
Associate software with MUL file on Mac

The procedure to change the default program in Mac OS

  • From the drop-down menu, accessed by clicking the file with MUL extension, select Information
  • Proceed to the Open with section. If its closed, click the title to access available options
  • 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 MUL extension. Next, click the Continue button to finalize the process.

Step 4. Ensure that the MUL file is complete and free of errors

You closely followed the steps listed in points 1-3, but the problem is still present? You should check whether the file is a proper MUL file. It is probable that the file is corrupted and thus cannot be accessed.

Check MUL file for viruses
1. Check the MUL file for viruses or malware

If the MUL is indeed infected, it is possible that the malware is blocking it from opening. Scan the MUL file as well as your computer for malware or viruses. If the scanner detected that the MUL file is unsafe, proceed as instructed by the antivirus program to neutralize the threat.

2. Ensure the file with MUL extension is complete and error-free

If the MUL file was sent to you by someone else, ask this person to resend the file to you. It is possible that the file has not been properly copied to a data storage and is incomplete and therefore cannot be opened. It could happen the the download process of file with MUL extension was interrupted and the file data is defective. Download the file again from the same source.

3. Check if the user that you are logged as has administrative privileges.

Sometimes in order to access files user need to have administrative privileges. Log in using an administrative account and see If this solves the problem.

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

If the system is under havy load, it may not be able to handle the program that you use to open files with MUL extension. In this case close the other applications.

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 Ultima Online Multi Format file. It is possible that one of the available system or driver updates may solve the problems with MUL files affecting older versions of given software.

Do you want to help?

If you have additional information about the MUL file, we will be grateful if you share it with our users. To do this, use the form here and send us your information on MUL file.

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