If not all of the correct files exist on your server then viewers of the site might experience issues such as:
• Incorrect Positioning, Formatting, Sizing
• Unexpected Interactions (ex. Widgets will fail to work)
• Missing Images
When the warning appears one of several possible problems could exists. Below is a list of the most probable causes:
1. One or more files are missing from the server or the permissions are set incorrectly. (The browser can't access one of the site's files) On server systems, files and folders are given attribute settings called permissions that tell the system what actions can be performed with these files, and who is allowed to perform them.
2. Files on the server are from mixed versions of Muse or mixed versions of your site (i.e. mypage.html from a different version of the page than mypage.css).
5. Also very rare, but we've had cases where the server side caching provided by BC fails to properly clear the cache for some files when new versions are published. If this occurs the server side cache will clear after a period of time, or BC support can explicitly force the cache to be cleared. Again, this one is very rare, but it has occurred.
6. Problems at the hosting provider. If your hosting provider is intermittently not serving up all the files for a given page of the site, that will cause this warning message to appear. This is also very rare, but has occurred.
Of the issues listed above, options #1 and #2 account for the majority of reports for this warning. When a third-party FTP solution is used, the application commonly fails to upload everything that has changed. When either of these two are the cause, the warning is consistent in all browsers. To resolve this issue, you should delete all existing Muse files on the server and re-upload all of your files exported from Muse.
If you choose to use Muse’s internal FTP client (“File” -> “Upload to FTP Host”) then Muse will detect which files have changed and only upload those files. If you choose to export the Muse site (“File -> “Export to HTML”) and upload using a third party FTP solution, it is recommended to upload all files and folders exported from Muse and use the "only upload changed files" setting(s) within your FTP client (if it has such a setting) to minimize what's actually uploaded, rather than attempting to second guess what's actually been updated.