Since we upgraded to Confluence 7.3.4 we've found that several PowerPoint files would fail to render a preview.
I disucssed this with Atlassian support and it appears there's a bug that times out the preview for some files.
https://jira.atlassian.com/browse/CONFSERVER-59786
In the log files you'll see the following
Conversion interrupted while generating preview due to timeout (30 seconds).
What I find strange is that it appears no one else seems to be reporting this issue for the more recent versions of Confluence with the updated file preview plugin.
I can't find a resolution and who knows when Atlassian would fix this.
Has anyone experience this issue with the more recent versions of (Confluence 7.3.x onwards)?
If so have you fixed or it or just live with it?