If you have upgraded to DL Windows 5.4.2 and have had problems reading HID 26bit proximity cards, there is a patch file available on the software webpage of the Tech Library. Even if you don't use HID 26bit cards, I recommend that you install this patch file.
Make sure you read the README file included in the Zip folder and follow the instructions exactly to prevent any problems later.
Click here to go directly to the page where the patch file can be found.
Andy Phelps, CRL
Alarm Lock National Training Manager