Runtime Error 18 (Function not defined) indicates that there is a software or hardware problem. Runtime errors can be caused by conflicts between two or more software programs, memory problems, or if your computer has been infected by malicious software such as a virus or trojan horse.
Runtime errors can result in both program and system crashes, slow computer performance, disruptive error messages, and high CPU usage. In the case of malicious software, there can be additional issues.
Fix Runtime Error 18
To fix Runtime Error 18 and ensure your computer functions error free, it is highly recommended that you download and run the Runtime Error 18 repair tool Advanced System Repair. Click the button below to download the software.
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