The list of pages that have that MultiExcerpt on it are displayed. Clicking on the link will take you to that page.
If "Find Includes" is very CPU-intensive or slow on your server then your site is probably large enough that the DB query that it is using is reaching its limits.
The admin can disable the "Find Include" button for their site
If a user attempts the use the "find includes" feature and it has been disabled they will see this message
If "Find Includes" returns no pages and you know that the MultiExcerpt is included on at least one page:
"Find includes" is case-sensitive but MultiExcerpt Include is not: CMEP-87
If your MultiExcerpt Include uses an excerpt by including it using a name that has different case than the excerpt it will include the excerpt (eg. 'MyExcerpt' vs 'myexcerpt')
The "Find Includes" button will NOT find any MultiExcerpt Includes that include an excerpt using the "wrong" case.
eg. for an excerpt named "MyExcerpt" none of the includes that include it by using the name "myexcerpt" will be found
Users who override the auto-completion in the drop-down for setting the excerpt name in an include macro are subject to this problem.
If "Find Includes" is slow or returns HTTP 504 gateway timeout errors:
Atlassian has been constantly improving Confluence for the scalability of large sites. The "Find Includes" feature relies on Confluence to efficiently query large sites. If you have a large site you should consider staying up to date with the latest Confluence Server upgrades.
Confluence confluence indexes are not always correct because of bugs in Confluence and you should consider rebuilding the indexes after a Confluence Server upgrade or when you are experiencing performance problems with your site. See Atlassian's guide for rebuilding Confluence content indexes:Content Index Administration
Atlassian recommends keeping large sites clean to help with the performance and scalability of content queries. See Clean up your Confluence site in the Confluence 7.10 release notes.
It is possible that your connection to the page was closed before you get the results of the query of multiexcerpt-includes
This can be caused by low timeouts on your Confluence or web servers, or configurations of your browser environment
If all else fails, then your site may just be too big for your database to rapidly query the content tables to find pages that have Multiexcerpt macros that point to your Multiexcerpt Include. In that case, you may not be able to use the "Find Includes" feature and should disable it from the admin tool if it is causing trouble for your users or your servers