You may encounter this error for the following reasons:
Macro security is set to:
Very High and the application encounters a signed macro, but the macro was automatically disabled. Use the following procedure to enable the macro:
Select the Tools menu option and then select Macro and Security. In the resulting Security dialog, set the security level to High by clicking the High radio button.
Close the file and any other instances of the application currently running on the computer (close all applications that also use the application you are currently running).
Open the file again and examine the certificate of trust details and set the Always trust macros from this publisher box if you trust the certificate issued by the publisher.
Click the Enable button to allow the macro to run.
High and the application encounters a signed macro, but you selected Disable when prompted by the macro warning dialog when opening the file. Use the following procedure to enable the macro:
Close the file and any other instances of the application currently running on the computer (close all applications that also use the application you are currently running).
Open the file again and examine the certificate of trust details and set the Always trust macros from this publisher box if you trust the certificate issued by the publisher.
Click the Enable button to allow the macro to run.
High or Very High and the macro was not signed and was automatically disabled by the application. Use the following procedure to enable the macro, if you have verified you can trust the source of the unsigned macro:
Select the Tools menu option and then select Macro and Security. In the resulting Security dialog, set the security level to Medium by clicking the Medium radio button.
Close the file and any other instances of the application currently running on the computer.
Open the file again and click the Enable button when prompted to allow for the unsigned macro to run.
When you have accepted the macro, return the macro security level to its previous setting.
Another instance of your application has a lock on the security settings and is disallowing any changes to security settings.
It is recommended to close all Office related applications or other instances of the same application when you attempt to make changes to your security settings.
Visual Basic for Applications (VBA) is not installed on your computer.
If VBA is not installed, it is not possible to accept certificates of trust attached to VBA macros. Therefore, any VBA macro attempting to run, even with an attached certificate of trust, cannot be run because the necessary macro interpreter is not installed on the system. Two scenarios can cause this error:
Your administrator chose not to install VBA
The version of Office you are running does not install VBA by default
If you are running an instance of Office that does not provide VBA as an installable feature, you will need to upgrade your version of Office to run VBA macros.
The certificate of trust is invalid - (when this occurs, you cannot select the Enable button).
The certificate is no longer trusted, was revoked by the issuing authority, or is damaged. There are several other possibilities which you may need to explore as to why the certificate is no longer recognized as valid by your system. It is recommended that you not trust or run a macro that has an invalid certificate.
A troubleshooter help topic is available online regarding this issue.
More information about this error message online.
