If your SD Card is not detected in Device Manager, it can be caused due to outdated drivers, hardware issues, etc. Use these fixes to resolve this issue.

Download Realtek USB Card Reader Driver 10.0.17763.21314. Driver update in Input Devices. OS support: Windows (all) ...

The bhtpcrdr.sys file is a card reader driver and is related to O2Micro SD Reader Driver from BayHubTech/O2Micro. The file is located in the \%Windir%\%System%\drivers\ directory.

Steam Deck is a PC, and other applications and OSes can be installed. If you're installing Windows, you will need a few additional drivers to have the best experience. Links to these, along with ...

Update March 14th, 9:42PM ET: Valve says it’s reproduced the bug I was seeing with SD cards vanishing in Windows, and has uploaded a new SD card reader driver that it hopes will fix the issue.