Cannot access all my folders from my SDCard via USB I plug in the USB cable to my computer. I click on Open Device to view files, I get to the root of my SDCard. The problem is that there is a directory missing. 

I can see it with my file manager on android but not on the computer. 

Any ideas why? I created this folder with an app I am developing.
You could try installing the Rescan SD Card! app and running it. You don't mention what phone you have sometimes you need to tell Android to scan the sd card to pick up changes.

This answer over at StackOverflow appears to suggest that sometimes the MTP cache gets out of date until a reboot of the phone or an app such as Rescan SD Card! is used. This no longer works as of Android 5.0.2, and a reboot of the device is the only fix.