Has anyone experience any issues with IE10 and designer view? We recently u

Has clearing the cache solved the issue?
Is this Appian 7.3 running the latest hotfix?
What is the error they were getting?

IE 10 should be compatible with v7.3. A more detail description of the behavior will give us a better understanding of the situation. Also check to make sure that the zoom is set to 100%

forum.appian.com/.../System_Requirements

2 ideas.
1) Be sure Hotfixes for 7.3 are deployed. It sound similar to issue fixed for AN-51567. See forum.appian.com/.../Hotfixes
2) Check your web/app server settings for whether it is instructing the user's browser to check for updates files. Typically, the Expires header and similar settings. If the infrastructure isn't set to check for updated files, you will see cache issues like this. The only work-around will be for the user to delete their own browser cache. However, adjusting the app/web server settings now will make future software updates avoid this issue.

Clearing browser cache does solve the issue and we do have hotfix B installed.

The browser doesn't through an error but I have seen it where the tabs in designer are not displayed. One user said he had a blank screen.

Myles, Is this a setting on the application server and if so, where can I find it?

There are lots of different configurations on caching, expirations, etc. It will depend on items outside of Appian like web servers, app servers, load balancers, etc. Here are some ideas to get started.
www.google.com/

ok, my thought after reading your post a second time was that maybe the app server had the ability and we didn't have it configured.