Galaxy S9+ rebooting with SD card installed

[Sme8]

I have an S9+ that won't stop rebooting once it starts and won't power.  It seems to be related to the screen locking and/or the fingerprint sensor or the SD card.  I've done a factory reset, all sorts of power off options, disabling all screen lock security. 

Why do I think it's screen lock?  When I go to unlock, it seems to reboot.  Could just be timing.  1st Q: how do you turn off the fingerprint sensor?  I'm not using it, but haven't found a way to actually turn it off.

I took out the SIM and SD card and it seemed to be stable.  Added back the SIM card, and still stable.  I can put in the SD card and it seems to sometimes start the rebooting cycle again, but not always.  Q2: Why would the SD card possibly cause reboots?

Q3: If I send it to Samsung, about how much would it cost?

[Tiger77]

See if plugging it into your laptop or computer recognizes it as the device it is or if a different description pops up(and try this with your SD card inserted in phone and see if you can access it's contents and look them over. If you downloaded any APK files or any new apps or download anything else recently before power and reboot problem started? If so delete cache delete data and uninstall see if that works

[Sme8]

The last time I had this issue, I had it plugged into my computer and did a manual backup of all files while it rebooted all day. 

So I've narrowed it down to the SD card as it does not reboot with it out, and starts rebooting with it in.  While copying the files (in Windows with a card reader) I ran into a corrupt files in the following locations:

data/com.samsung.android.svoice

data/com.spothero.spothero/cache.

obb/microsoft.office.onenote

Example:

I was also unable to delete them.  I have svoice disabled and am aggressive about keeping apps like spothero from starting.  My guess is that once OneNote tried to start or just scanning the files for what ever reason, the system gave up and restarted.  Repairing the card via Windows did not work. In the middle of some other things now, so I'll try to reinsert as is to see if I can get the phone to start rebooting a couple more times and then format and retry.

[MrJell_Lee]

if the SD card's contents are cleaned out, and still causing reboots... maybe the card is shorting? Either by some impurity or physical damage.

As for the repair cost, it's really dependent on what is being fixed... but either way the labor fee is what's going to destroy your pocket. I'd check the warranty and see if anything is left on the device, chat with the agent on samsung website or call them to check (I don't know the full details of what warranties exist, as many probably would too, so worth asking i suppose).

Another option you have is submitting the issue report to Samsung Members app post issue recreation, see if the techs are able to help figure out the cause. Who knows, you might receive a fix that doesn't cost you.

[Sme8 · Accepted solution]

Thanks for the suggestions and additional info folks.  The SD card format seems to have fixed it.  On all of the searches, this was not on them and should be considered before clearing cache and phone reset.