iPhone: Application Install Fails With "Invalid Signer" Error

Question

The iPhone is attached to a Mac runnning the latest iTunes version and I am 100% sure that her UDID is in the provisioning file. Her iPhone has not been jailbroken and we even restored it to factory settings.

I am having trouble installing our development build on this one iPhone. The error is:

the application "[Application Name]" was not installed on the iPhone "iPhone" because the signer is not valid

I am 100% sure that the UDID is accurately entered in the provisioning file and that they correctly copied the right provision file/build combo. This same combo has been successfully installed on over a dozen iphones.

We have been able to install this on some devices with no problems.

Edit:

From comments to an answer:

We can install it on 100 iphone with our account. We have about 40 iphones in this provisioning profile and it works on 38 of them.

Answer 1

I had a fix that seemed to work for one user who was having troubles:

1. remove all offending profiles and apps
2. restart
3. add back provisioning profile FIRST
4. sync device
5. now add app resource
6. sync again to get app on device

the offending machine was a windows box... dunno if that makes a difference.

If someone else gets this issue - try this and let us know if this is the actual fix or workaround! This goblin has rarely been seen and solved with the same steps.

this was my reference for the fix idea:

http://iphone.forums.wordpress.org/topic/installing-beta#post-1194