ActiveX is a series of high-level internet technologies introduced by Microsoft during the late 90s. Many ActiveX technologies are no longer used today, except for a few like ActiveX Control, ActiveX Data Objects, Active Directory or NDTS, Active Server Pages, and Active Scripting.

Active X is a set of rules that dictates how Windows applications should share information. It is not a programming language and can be written in different languages such as Java, Visual Basic, and C++.

One of the most popular ActiveX technologies is ActiveX Control. It is comparable to Java Applet but it's more powerful since it has full access to your Windows OS (operating system). However, ActiveX control can also cause software and data damage to your computer due to this 'power'.

Active X errors can cause your applications to fail, your system to crash or downright prevent you from opening your documents.

To minimize ActiveX errors, a registration system was developed by Microsoft so users will be able to identify as well as confirm any Active X control before it gets downloaded by their system.

ActiveX errors do not occur for ActiveX control alone but for other ActiveX technologies as well including ActiveX scripting, which is used by to embed interactive components into HTML texts. Basically, ActiveX errors in whatever Active X technology are caused either by particular browser settings or by misconfigured system files in your computer or both.

How to Fix ActiveX errors

Once your computer flashes an ActiveX error notice, the first thing to do would be to check your PC's settings.

1. Pull down the Tools menu and go to Internet Options.
2. In the Security tab, click the Custom Level button.
3. Make sure that your security level is set to Medium.
4. Check also if the following settings are enabled:
- Run ActiveX controls and plug-ins.
- Script ActiveX controls marked safe for scripting.
- Scripting.
5. Save your settings and find out if the problem has been fixed.

If the above doesn't work, or your settings are correct, then the ActiveX error was likely caused by a misconfigured system file, which needs to be reset to default settings.

1. From the Start menu, click Run.
2. Type regsvr32 msxml3.dll and then click ok. A dialogue box will then notify you that the system file had been reset.
3. Check if the ActiveX errors are fixed by opening a new browser window and closing all the existing ones.

Lastly, to avoid Active X errors altogether, consider using a registry cleaner to avoid the hassles ActiveX errors bring. Registry cleaners help make sure that your system is clean of any unwanted and poor-quality files that can be harmful to your system.