4. With scanner off, PRESS and HOLD SQUELCH KNOB and turn the scanner on while continuing to hold SQUELCH.
As the scanner powers up, you will here a beep. Let go of the SQUELCH KNOB and your display will read
USB MASS STORAGE.
As mentioned by
@dave3825 above, there is no need to hold down the squelch knob to enter the mass storage mode. Your post is the first and only time it has ever been reported as being a necessary step. Many of us here on RR have been using the Uniden SD card scanners since the Home Patrol 1 was released 14 years ago and have never had to use that step to enter mass storage mode on any of those scanners, nor is it stated in any of the Uniden owner's manuals as being a necessary part of the process. Barring a defective USB cable, just connecting the cable to your PC will trigger the scanner's screen to select the mass storage mode. If the card in the scanner is corrupted, or it's a newly formatted blank card and you turn the scanner on with the USB cable
already connected to the computer, it may not go any further than the "SD Card File Error" screen. If this happens, leave the scanner on and just disconnect the USB cable and then reconnect it to reach the mass storage screen.
Hope this helps. I know how frustrating it is fighting with it for several hours. This seems to be a lengthly process but it worked for me.
Granted, the first time a new user sees the "SD Card Error" message it can seem like a daunting, scary and complicated process to recover, and some feel a sense of panic thinking that their expensive scanner is now damaged, or that they will they will cause damage to it when trying to recover. Rest assured, in the event that a simple SD card failure happens, no harm has come to the scanner and you can not cause any harm to your scanner during the recovery steps... even if you make errors during the process. Just start over again and carefully follow the steps.
The entire process of formatting the card, running the "Clear User Data" process, and then writing to your scanner from Sentinel to re-populate your programming data on the card is a straight forward procedure that only takes a few minutes to get you up and running again from start to finish. The comment of "fighting with it for several hours" just doesn't make any sense. Using an external card reader to perform the steps will be even faster (having faster read/write speeds) than doing it in the scanner. It's not too often that an SD card becomes so corrupt that it can't be reformatted and re-used, but having a couple of extra new cards on hand is always a good idea.
Aside from having your scanner's customizations and programming kept in Sentinel, the best advice by far, for the fastest and simplest way to recover is to
prepare in advance for when an SD card error might happen. Make complete backups of your SD card! When you have your scanner programmed the way you want (or whenever you make changes), copy the
entire contents of the SD card to another formatted card, or copy the contents to a dedicated folder on your computer. Then if you get the SD card error, you can reformat that card and quickly copy the backup files from your computer to it (or to a new card) and be done with it, or just pop in the backup SD card that you already copied the files to earlier. If you travel with your scanner, keep 1 or more spare, programmed cards with you. If you have a card failure when not near your PC, you can be back up and running in a matter of seconds.
And a couple of things that seem to frequently trip up new users..... when a new (or newly formatted) blank card is put in the scanner without any files on it, the scanner
will still power up with the "SD Card Error" on the screen. The scanner will only boot up completely once the card has the files put on it from the clear user data process, or from your backup files copied to the new card. Also, when Sentinel's clear user data process is used on a new (or newly formatted) blank card, the first window that opens on your PC after starting the process won't recognize that card until the "Display all drives" box is checked.... just be sure to select the correct SD card (if you have more than one connected to your computer at the time).
And to repeat some very sage advice that
@ofd8001 recommended above.... don't over think it!
.
