i was trying to install my iphone application from testflight. it installs perfectly on few devices but in some after installing about 80 percent it gives an error \"Unable to d
Most common issues that cause this are (from testflight's website):
for me it turned out that my client's ipad was running iOS 4.2.2 and my project supports 5.0+.
I had the same problem as @mohitum007. In my case the developer of this App included an expiry date in it.
As workaround I set the date backwards to a past date (e.g. last month). Then I could install it and use it.
Also when I set the date back to normal, the already installed App didn't start up anymore. I contacted the company of this App to send me an updated version.
Sidenote: I found out that users from other Apps had the same problem but reversed: it won't install or start before a certain date.