There's no way to know if a report is bad unless it's opened. If it works in Desktop then is should almost certainly work on Server. The one thing that could cause it to fail would be no datasource driver e.g. connecting to a MS SQL db but no MS SQL driver is installed.
VizCrawler is an internal Tableau tool that uses some code from TabJolt to iterate over vizzes and capture errors it encounters loading them, as well as record the time it took to render them (end to end). It's unfortunately not publicly available at this point. You could certainly script out tabcmd calls to export the images for each viz. It'd be single threaded but it'd do the job, I think.
I havent tried it yet, but the latest version of tabjolt has an auto-discover mode.
Here is what the documentation says
Also, you may want TabJolt to auto-discover all the available views across all sites on the server. Instead of specifying each individual view to load, you can set the auto-discover mode to find them all. This is done by changing the auto-discover mode in c:\tabjolt\config\PerfTestConfig.yamlfrom“vizDataSource:csv”to“vizDataSource: web”.
Tabjolt can be found here
This may solve your issue.
All the best
thanks Glen. I happened to run across this wildcard feature yesterday (in the tabjolt doc), but didn't right away connect it to this thread.