Quote Originally Posted by C4a0s17 View Post
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1) just curious but arent most micro SD cards sold as UHS nowadays?

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Not that I'm aware of--most, if not all, SDcards <32GB are non-UHS. I've encountered mounting/reading issues with the Sandisk 32GB UHS-I uSDcards in some Garmins and smartphones. I've two phones that are identical, one could be reliably used with the Sandisk 32GB UHS-I uSDcard, while in the other it would not--requires eject and re-insertion of the uSDcard after power-on in order to be intermittently recognized. Once recognized properly, the uSDcard would work fine until the next boot-up/power-on.

I've also encountered exactly the same symptoms you've described with the Sandisk 32GB UHS-I uSDcard in a few of my nuvis (i.e., 1350, 1390 and 1450). Nowadays, I just use cheap 8GB Class 4 uSDcards in them, and they've been consistently reliable unlike the Sandisk 32GB UHS-I uSDcards. First couple times I encountered this problem, I thought I got faulty ones, so I exchanged them, but still the same issues.

You should try lolypop000's and Ellinas's suggestions first though...