The security warning is not due to your Liberty Reports or Office Connector software and does not indicate that there is a problem with the file. Microsoft Excel (like other Office applications) includes security features that are designed to help protect your computer from harmful content. As an example, Office documents (Excel, Word, Access, PowerPoint) can contain macros. If you received a file from an untrusted source, it's possible that it could contain macros that would be harmful to your computer or jeopardize your data if those macros were allowed to execute when the document is opened. By default, the security features of Microsoft Office disables untrusted macros and allows you the option to allow them to execute or not. Likewise, Microsoft Office documents can also contain links (i.e., Data Connections) to your company data. A document containing Data Connections received from an untrusted source could also be potentially harmful for similar reasons. If the query of the Data Connection were allowed to execute, damage could be done to information or sensitive information could be exposed. Again, for this reason, Data Connections within a document from an untrusted source are disabled by default and you have the option to enable them.Solution
In the case of Excel files that contain Liberty Reports or Office Connector functionality, you may wish for the security warning prompt to be automatically disabled (because you trust the content of these files). You can control this via the the Trust Center Settings in Excel Options. Additionally, a digital signature is a way to identify that a document is from a trusted source. All files provided by Event 1 with your software include Event 1's digital signature.
The following Microsoft article describes the security features and how to control the security prompt: