When an operating system or a computer processor receives an instruction from a program that does not recognize it and can not be processed, it may issue something known as an illegal operation. The following are reasons for an illegal operation on a computer.
TSR’s or third-party programs
TSRs or third-party programs running in the background are one of the most common causes of illegal operations. If there is an illegal operation that occurs when a game or program is running, close all other open programs and the TSR runs in the background.
If you no longer receive illegal activation messages after you remove these programs, we recommend that you restart the computer. Once it is finished, disable or terminate the task for each program or TSR one by one to determine which program is causing the illegal operation.
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Error in program coding
Verify that the program that is causing illegal operations is compatible with your version of Windows and check with the developer to make sure that no patches or updates are available. There is nothing like the ideal software program, and it is not common to issue multiple patches and updates during a software life cycle.
Data is not being read properly from source
When you run a program or game from a CD-ROM and you receive an illegal operation, verify that the CD-ROM is clean. For additional information about how to clean your CD-ROM drive or CD-ROM drives, see our cleaning page.
If you are running a game from a floppy disk or other removable drive, verify that the disk does not contain any physical errors by running ScanDisk.
Installing a program or game on a hard drive that has errors or is highly fragmented
Make sure that the drive is not fragmented or corrupted by running ScanDisk and Defrag on the drive.
If there are errors on the hard drive, they cause the program or game to run improperly and can cause illegal operations.
Corrupt files
Corrupt, bad or lost files can cause illegal operations. Try uninstalling and reinstalling the program, causing an “illegal operation” to verify that any corrupted, corrupted, or missing files are replaced or repaired during the reinstallation.
Memory managers
If you are running a memory manager, it is recommended that you temporarily disable or uninstall this program to verify that it does not cause illegal operations.
Bad, incorrect, or outdated video drivers
Incorrect, incorrect, or outdated video drivers can cause illegal operations when you move the mouse, highlight, or set high requirements on the video card. Try to reduce the resolution to make sure that the current settings do not cause the problem.
How to set the resolution in Microsoft Windows.
How to set Resolution or Change Resolution / Converter in Windows 3.x.
If you still experience the same problem after you adjust your video settings, verify that your computer is using the latest video card drivers by visiting the Video Drivers section on your computer.
Computer virus
Because computer viruses and other malicious software are loaded in memory and can modify files incorrectly, they may cause “invalid operation” error messages. Make sure that the antivirus tool is installed on your computer and that it is up-to-date.
Added hardware
If a new device has recently been installed (for example, computer memory) in your computer, it may conflict with which drivers should be installed with other computers. Remove any new hardware and related programs temporarily to make sure that it does not cause the problem.
Bad Memory, invalid bits or physically bad memory
Bad memory can cause illegal operations. If you recently added memory to your computer, remove the memory to make sure it does not cause the problem. If you have not added any memory recently and have tried all the above recommendations, test your computer memory.
Corruption or problem within Windows
Because Windows controls memory operations and all system operations if any part of Windows is damaged, it may cause illegal operations. If you try all the suggestions above, we suggest reinstalling Windows.
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