Unable to read the map SD Data

My navigation system on my 2016 Prius has stopped working. When I turn on the car, the map will usually come on screen for a couple of seconds, then the following message is displayed:

Unable to read the map SD Data.
Check the map SD.
If necessary, consult your dealer.
​

It had been doing this on and off for a number of months but would usually come back on when I restarted the car and stay on. Now the map is gone completely.

I've removed the SD card, cleaned the contacts, and reinserted it. Doesn't make any difference. I think I bought the SD card in 2020 and it had a 2019 map.

My question is, does this error look like it's just a problem with the SD card that an updated map would fix, or could it be a problem with the card reader?

Thanks for any insights/experiences with this problem.

 

I probably didn't throw it away because I tend to keep everything, but I don't know if I'll be able to find it! Good idea though.

 

Update:
I called my local Toyota dealer and asked whether this message indicates a bad SD card or something more serious. He told me I would need to bring it in so they can check it out. When asked how much that would cost, he said the diagnostic check is $150. Well, my map needed updating anyway, so I might as well try installing a new map first to see if the problem is fixed, so called the parts department to ask how much the updated map costs. He told me $150. I asked for the serial number, went on Amazon and bought it for $26. Popped out the old SD card and put the new one in. The new map came up immediately and has been working ever since.

 

Update:
I called my local Toyota dealer and asked whether this message indicates a bad SD card or something more serious. He told me I would need to bring it in so they can check it out. When asked how much that would cost, he said the diagnostic check is $150. Well, my map needed updating anyway, so I might as well try installing a new map first to see if the problem is fixed, so called the parts department to ask how much the updated map costs. He told me $150. I asked for the serial number, went on Amazon and bought it for $26. Popped out the old SD card and put the new one in. The new map came up immediately and has been working ever since.

 

Update:
I called my local Toyota dealer and asked whether this message indicates a bad SD card or something more serious. He told me I would need to bring it in so they can check it out. When asked how much that would cost, he said the diagnostic check is $150. Well, my map needed updating anyway, so I might as well try installing a new map first to see if the problem is fixed, so called the parts department to ask how much the updated map costs. He told me $150. I asked for the serial number, went on Amazon and bought it for $26. Popped out the old SD card and put the new one in. The new map came up immediately and has been working ever since.

 

Sorry about the repeat replies. I don't know how to delete all the duplicates.