One of my colleague today reported that she can’t download/save the report from our TMS (Transport Management System) web application. She is using Internet Explorer 10. She complained that all along she can download, but just today suddenly can’t.

So I tried to simulate her issue in PC. Somehow I can’t. I always successfully manage to download the report no matter how big the data is. So there should be something wrong with her browser.

Connecting to her PC through TeamViewer, I can see that the download dialog still open as expected.

It’s just that when you click Open or Save, it will throw error.

My first try was to add the site under trusted connection, with the lowest security level. Still can’t download.

Asked her to close the IE then open IE again, still can’t download.

Asked her to reboot PC, open IE, still can’t download.

I scanned her installed programs hoping to find programs that wrecked her download, can’t find anything suspicious.

Puzzled, I opened IE’s Developer Tools (F12), switched to Network tab, and start listening for packets. When I clicked the download button, IT WORKS!!!

Although problem is solved, I still puzzled why the download failed in the first place. If this happened again to other people next time, I will install packet sniffer for sure.