How to fix an HTC U12/U12 Plus that cannot read SD card, SD card not detected error [Troubleshooting Guide]

Most of the latest Android smartphones support SD card for extra storage. The built-in storage capacity may not be good enough to allocate additional files especially for users who are fond of downloading complex apps. Thus, smartphone manufacturers considered SD card among the key features to embed into their respective devices. And to make use of the extra storage, you will need to secure a compatible SD card and then mount it in your phone. Once mounted, you’re all set to store files in it. Since the Android Marshmallow rollout, users are already able to merge internal and external storage and set SD card as default storage. This therefore allows you to save new apps and files straight to the SD card.

However, there are times when the used to be very simple SD card mounting doesn’t work as intended. Like many other features, SD card functions of your phone can also be troubled by errors and glitches. Among the most prevalent issues concerning SD card is on the device that’s unable to read or detect the card, as depicted by the SD card not detected error. This continues to emerge among the common problems encountered by Android users including those with the HTC U12/U12 Plus smartphone. Mapped out below are generic solutions to deal with issue. Read further to find out what to do when suddenly your new HTC smartphone fails to read the SD card.

But before anything else, if you have another issue with your phone, drop by our troubleshooting page as we have already addressed hundreds of issues reported by the owners. Odds are that there are already existing solutions on our website or at least, there are similar problems we already fixed. So, try to find ones that are similar or related to your problem. If you need further assistance, however, feel free to contact us by filling up our Android issues questionnaire.

First solution: Reboot or soft reset your phone.

The simplest solution you can try on first is a soft reset or device restart. This effectively clears random issues that are associated with minor software errors on the phone. It also help refresh the memory for better and smoother performance. Here’s how it’s done:

  1. Press and hold the Power button for a few seconds or until the menu options appear.
  2. Then tap Restart.
  3. Alternatively, you can press and hold the Power button for at least 10 seconds and then release the button when the HTC logo appears.

No need to back up files beforehand because this method won’t affect saved data on the phone.

Second solution: Unmount microSD card then reseat it.

The device may be telling you the truth that it cannot read the SD card because it’s loose or dislodged from the tray. To rule this out, reseating the card is recommended. Before you do so, it’s imperative to unmount/eject the SD card first to prevent data corruption or damaging the card itself. Here’s how to unmount an SD card on your HTC U12/U12 Plus:

  1. Tap Settings from the Home screen.
  2. Select Device Maintenance.
  3. Tap Storage.
  4. Tap the Menu icon on the upper-right and then select Storage settings from the given options.
  5. Scroll down to Portable Storage then tap the Eject icon next to the name of your SD card.

After unmounting or ejecting the card, you can now remove it safely from your device. Proceed with these steps to remove and reseat the SD card on your HTC U12/U12 Plus:

  1. Power off your phone completely.
  2. Hold the phone face up.
  3. Insert the tip of the eject tool that came with your phone into the tray eject hole. If you don’t have the tool, you can use a small bent paper-clip instead.
  4. Gently push the tip all the way into the hold until the tray ejects.
  5. Then pull the tray out.
  6. Carefully remove the SD card from the slot then examine it closely for any visible signs of damage. If everything looks good, place it back into the card slot. Be sure to place the card with the gold contacts facing down.
  7. Align the cut-off corner of the microSD card to the notch on the card holder.
  8. When both the nano SIM card and microSD card are secured in place, insert the tray back into your phone. Make sure the tray is fully inserted and does not protrude from the slot.

Turn on your phone and then try to access the SD card storage. If necessary, mount the SD card again to prepare it for use.

Third solution: Erase or format microSD card.

Formatting the SD card may be necessary if the problem is due to data corruption. Data segments or the SD card itself might have been corrupted. As a result, the SD card couldn’t be read by the device. To rectify this, follow these steps to format or wipe the SD card on your HTC U12/U12 Plus:

  1. Swipe up from the Home screen then tap Settings.
  2. Tap Storage.
  3. Navigate to Portable storage then tap the Menu icon (spinning wheel figure) next to the storage card name.
  4. Tap the option to Format as internal.
  5. Then select Erase & Format.
  6. Tap Format to confirm.
  7. Follow the rest of the onscreen instructions.

All data saved on the SD card are deleted in the process. Any malware or virus attached to any of the SD card files will also be rid off. So you’ll have a totally clean and same as brand new SD card afterwards.

Fourth solution: Update phone software to the latest version.

Keeping the phone software up to date is recommended to keep it as bug free as possible. Should the problem is inflicted by some malware on the phone system, installing an update can potentially deal with it as updates offer bug fixes. To manually check for new software version on your HTC U12/U12 Plus, follow these steps:

  1. Slide the Notifications panel open.
  2. Then tap the system update notification.
  3. If necessary, tap Update over Wi-Fi only if you don’t want to download the update using data connection.
  4. Then tap Download to continue.
  5. Wait until the download is finished then select the option to Install now.
  6. Tap OK to confirm.

Allow your phone to finish updating and then reboot it when done. Retry to access the SD card storage and see if it’s already working this time.

Fifth solution: Wipe cache partition on your phone.

System files that are stored as cache can also cause the same issue when they get corrupted. It’s usually recommended to wipe cache partition if certain apps or the device itself is acting up after installing a new update. If the SD card not detected error started to occur after updating your device software, then try these steps to clear system cache and refresh its operating system:

  1. Power the phone off completely.
  2. With the phone powered off, press and hold the Volume Down button while turning the phone on.
  3. Continue to hold the Volume Down button until the bootloader screen is displayed.
  4. Press the Volume Down button until Recovery is selected.
  5. Press the Power button to confirm selection. The phone will then seem to reboot and the screen will turn black for 15 to 30 seconds.
  6. Wait until the recovery screen is displayed then continue with the next steps.
  7. Hold the Volume Up button and then press and release the Power button.
  8. Press the Volume Down button repeatedly until Wipe Cache Partition option is highlighted.
  9. Then press the Power button to confirm selection.
  10. Press the Volume Up button repeatedly after the process completes.
  11. Press the Power button to select Reboot system option.

You may consider opting for a full system reset or master reset if the problem persists. This may be the key solution if touch bugs or fatal system errors are at fault.

Other options

Consider replacing the microSD card with a new one that is compatible with your HTC U12/U12 Plus if none of the prior methods helps and none of your other devices is able to read the same SD card too. The SD card might have been damaged and no longer works. To ensure that you’re using the right SD card, you may contact HTC support for recommendations. If your SD card is detected by your other phones or computer, it means that the problem is on the phone. In that case, you can take your device to an authorized service center and have it examined by a technician instead.

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