The macro might not be from a trusted source If the security level is set to Medium or High and you open a file or load an add-in program that contains digitally signed macros that are not from a trusted source, you receive a macro warning. If you are sure that you trust the macro developer, add the name to the list of trusted sources.
The macro might contain a virus If you don't expect a file to contain a macro, you might have a virus that is adding a macro virus to the file. Check your computer for viruses and then try to get an uninfected copy of the file from the source.
The macro might be in a temporary file that you downloaded from a Web site If your virus scanner tells you that it has removed a virus in this file every time you open it, you are removing the virus from the temporary file only and not from the original file on the Web server. Check your computer for viruses and then notify the source about problems with the original file.
The database may contain legitimate macros Microsoft Office Access cannot distinguish between safe and unsafe macros. If you know that these are legitimate and safe macros, you might want to digitally sign the macros and add your name to the list of trusted sources.
The Trust access to Visual Basic Project setting in the Security dialog box is unavailable.