Can i connect via adb to tablet that is stuck on welcome screen and won't boot? I am tring to connect via adb to tablet that is stuck on welcome screen and doesn't want to boot. If i run 'adb devices' i get this:

E:\minimal_adb_fastboot_1.4.1_portable&gt;adb.exe devices
List of devices attached
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
0123456789ABCDEF        unauthorized


And if i try to connect i get this:

E:\minimal_adb_fastboot_1.4.1_portable&gt;adb.exe connect 192.168.100.13
unable to connect to 192.168.100.13:5555: cannot connect to 192.168.100.13:5555: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (10060)


Is it possible to connect to the device if the operating system is not fully loaded?
It is possible to connect to the device through adb when it is stuck on welcome screen or even when it is showing boot animation. The problem in your case is that your device has not authorized the connection. Under normal circumstances, when you connect through adb a dialog is shown on the device for user's confirmation to proceed. Until the user agrees, you can't do anything good with adb. And since you're stuck on welcome screen, I see no way to agree to the dialog. 

That been said, if you can somehow manage to flash a compatible custom recovery you can pretty much salvage all of your data. You might also be able to solve this adb unauthorized issue.