**Original bug report**
I am uploading PDFs to Wikimedia Commons using UploadWizard. Most of them worked. But I have 27 files where I get the error: "This file might be corrupt, or have the wrong extension." They work just fine on my computer and I still get the error even after I deleted the files and re-downloaded them from my source to be safe.
Attached is one of the files that did not work. One of the files that did work: https://commons.wikimedia.org/wiki/File:NIOSH_Manual_of_Analytical_Methods_-_8304.pdf
I am re-opening this bug now that I know it was not just a one-time fluke. Also applies to other sorts of files and not just PDFs.
This is what happens: I am currently working on uploading hundreds of files to Wikimedia Commons. This means I can do 50 at a time, but given that I am only uploading a few hundred files, this isn't that terrible. But in a given session, after a certain number of uploads (around 100), UploadWizard starts rejecting all submissions with "This file might be corrupt, or have the wrong extension." I know for a fact that the files are not corrupt; in fact the UploadWizard even renders them correctly.
Yesterday (14 April 2016) I encountered this error, left the office, re-attempted the uploads around 90 minutes later and they worked just fine. I worked on another batch of uploads and got the error again. Changing your IP address does not fix the problem, since I tried from a different WLAN and the same problem still occurred.
I did more uploads this morning (15 April 2016) and I managed to upload 150 or so files before encountering the error again. This appears to be a recurring problem, and I would like to see it investigated.
A commenter raised the possibility of a throttle; if such a throttle exists, it should be properly expressed instead of being hidden behind an inapplicable error message. If there is not supposed to be a throttle, the cause of the error message should be investigated.