Assuming the Sony is showing up as an external drive in your file manager ...
You need to have the Sony Reader software installed to use the Sony with ADE.
You don't need to use the Sony Reader itseft, but the install also adds a driver that allows ADE to see the Sony.
(Irritating design by Sony)
Wow, that was a quick response.
Yes, when I look in explorer the 'Reader' shows as an additional drive There are three main folders, Books, DCIM and Sony Reader.
I do have the Sony Reader software installed on my PC (Windows 8). My PC is authorised. Currently my device is attached to it and its shown as a connecteion on the top bar.
How do I know if a driver has been installed that allows ADE to see my Sony device.?
Prior to receiveing your reply I deleted the version of ADE installed on my PC and have downloaded another version. When I opened the ADE program there was no reference to my device being connected although the ereader was connected to my PC via a USB cable.
It might be worth trying v1.7.2 if you haven't already.
Even if you get the Sony working with V2.0/2.0.1, ADE2.x has a bug that stops it working with the Sony and Overdrive library books.
(Get a Kindle if you want to guarantee you can't open Overdrive library books, at least in the UK.
If you are happy to buy all your books from Amazon I am sure it will provide a much simpler DRM life, though.)
I'm not sure how digital editions picks up the Sony driver, nor an easy way to find if it has.
I don't think it is a driver in the usual Windows sense, but Sony calls it that.
I'm not aware that is is important which order you install Sony Reader and ADE, but there could be some oddity there.
You could try the suggestions in http://www.migear.biz/Downloads/Cant%20see%20device%20in%20Adobe.pdf
As you can get your Sony books, I assume it is showing up fine in Sony Reader and that it is registered with a Sony account?
Just in case, from http://www.mobileread.com/forums/showthread.php?t=112026
I had to sign up for a Sony ebook store account and it authenticated my ereader. I can now open other files, turn on/off my ereader and not be blocked from the drm'ed book.
If you are an advanced user ...
I can see using the details available in ProcessHacker that ADE has loaded the following
DriveManager.dll, 0x54c0000, 56 kB, Drive Manager for MSC PRS, C:\Program Files\Sony\ReaderDesktop\appHelper\DriveManager.dll
fsk.dll, 0x5980000, 860 kB, , C:\Program Files\Sony\ReaderDesktop\appHelper\fsk.dll
libeay32.dll, 0x5a60000, 1.01 MB, OpenSSL Shared Library, C:\Program Files\Sony\ReaderDesktop\appHelper\libeay32.dll
msvcr71.dll, 0x7c340000, 344 kB, Microsoft® C Runtime Library, C:\Program Files\Sony\ReaderDesktop\appHelper\msvcr71.dll
PIM.dll, 0x10000000, 136 kB, , C:\Program Files\Sony\ReaderDesktop\appHelper\PIM.dll
ssleay32.dll, 0x54d0000, 204 kB, OpenSSL Shared Library, C:\Program Files\Sony\ReaderDesktop\appHelper\ssleay32.dll
USBDLL.dll, 0x54a0000, 120 kB, USB tools for MSC PRS, C:\Program Files\Sony\ReaderDesktop\appHelper\USBDLL.dll
Thank you again for your response. I am not an advanced user so Im going to connect to the two links you have listed in your reply sometime tomorrow (its quite late in the evening now). I will let you know (and just in case anyone else is having an issues well with their PRS-T1) hopefully very shortly.
Regards David A Jones.