Ultra Fit USB 3.0: Excessive Heat

I just received my Sandisk Ultra Fit USB 3.0 128GB Flash Drive with great excitement.
On package: SDCZ43-128G-Q46 and 80-56-14876-128G
On Flash Drive: BP160525497D and SDCZ43
I inserted my new Ultra Fit USB 3.0 128GB Flash Drive into my HP Pavilion Desk Top
and began copying my music and video files to it. I reached down to remove it
and it burnt my finger and left a blister. WTF ???
I’m 65 years old and have been in the computer industry for 35 years.
How can any company release such a flawed piece of technology.
This drive, in my opinion, should not be sold. They can cause USB port damage.
They should be recalled and replaced with safe units.
Sandisk, you burned my fingers and created blisters. There is no warning regarding
a burn hazard and handling instructions on your packaging.
I plugged your product into a 2.0 USB as instructed and I was burned.
Sandisk please contact me.

“I plugged your product into a 2.0 USB as instructed and I was burned.”

Are you sure it wasn’t a USB3.0 port? Mine’s been running reliably and less than blistering hot since I stopped using a USB 3.0 port for it.

…and this is a user’s forum, fat chance that Sandisk will reply here - especially on this product LOL.

It says USB 3.0 which I assume means designed to use in a USB 3.0 port. Backwards compatible with USB 2.0.

my computer has 2.0 on the front - even in a TV USB port or Andriod TV box this thing burns too hot for reality.

but thank you for your feedback

Well, if you think it gets hot in a USB2.0 port you’d freak at how hot it gets in a USB3.0 port LOL. It gets so hot that it shuts down after a couple minutes of being written to. I can’t beleive it didn’t burn up but it’ll start working again after cooling down.

I have just ordered a few of these (in total I have approx 8 of these USB3 32GB and 64 GB)

They were selling cheap.

I too noticed excess heat.

Does anyone have a link to an official Sandisk posting, saying that we do not have to worry about data loss ?

I can live with burnt fingers, as long as I do not risk losing data already stored on them

Potential loss of data could have me jumping off a cliff (as a Scot would be bereft if he thought he could lose data after all of those purchases)


PS If the answer is - Don’t worry Rob, you won’t lose any previous data on the drive


I have a suggestion for all of those concerned about the heat damaging the computer and/or the usb socket.

Purchase a USB 3 Extension cable (Male into your PC, and Female socket on the end of the cable).

If you plug the sandisk into that, there will be no risk of damaging your PC.


PPS If the answer to my first post is - Rob, you could lose data.

I will take my own suggestion, and have a wee fan blowing on to the end of the cable

(If everyone PayPals me $20 for that suggestion, it could keep me away from the cliffs)

I just use mine on a USB2.0 port - no prob.

I have the solution for you all.

I was using a usb3 extension cable and the sandisk 32GB was getting very hot.

(I previously had a sandisk OTG in there, and it too got frighteninly hot)

That cable had plastic shrouding over all of the female socket.

I looked through my previous ebay purchases, and found a 1M usb 3 cable with the female end bare metal (no plastic covering).

I tested the 32GB in it for 30 minutes, and just ejected it now, and it is slightly warm (NOT HOT)

I did not have any fan, and the room is 20C.

Another thing to be wary of, is ensuring you get a cable with a snug fit. For two reasons -

  • I have had total loss of data when wiggle occured at a crucial time (mind you that was an external pocket 2.5" drive)

  • A snug fit will help with heat transfer

The cable I previously purchased was most likely the same as this current ebay listing -

1M USB 3.0 Extension Data Cable SuperSpeed - A Male to A Female - AU STOCK


It was many months ago when I purchased mine.

I just rang the company, and they tell me that they have not changed supplier for 8 months, so there is a good chance that the current ebay listing (above link), is identical to mine.


PS I have just ordered some more, so I will report back to confirm whether they are the same. (should only takes days, as they and I, are both in Melbourne Vic Australia)

Just bought the UltraFit 64G, inserted it in the USB of my desktop and loaded some files onto it, about 40Gb and sure…the thing became hot as hell. Really hot, the thing that at first amazed me as a nice piece of engineering wasn’t, after all, that well engineered. Can’t be good for the internals to get that hot.

Upon inserting it in the USBport of my laptop, and using it in a more normal way, the temperature was much more acceptable, just hand warm, so I guess under  practical conditions, making a report, watching a movie, everything is acceptable.

But big data dumps seem to be a problem, and I really also hate to see it use that much battery power from the poor laptop’s battery.

I have a 32GB that seems to not overheat like my 128GB does. In any case the solution is simple - just use a USB2.0 port when writing large amounts data to it.

Sometimes i wish i had read reviews of products, even of A brands, before i bought them. 

So i bought the 128GB USB Thin of Sandisk to use for work related files so that i can quickly swap between my workstation and my travel laptop. After a few minutes in my travel laptop i also noticed the extreme heat of the USB stick, even though i wasnt using it at all. In the 3.0 USB ports of my workstation, same problem, although in my workstation it got so hot it actually hurt to touch the metal parts. In a 2.0 port it gets a bit warm, but nothing extreme. Unfortunately my travel laptop has no 2.0 ports…

Is there any solution for this? 

Yesterday i tested a few of the “solutions” on this forum on my 64GB’s.

First I attached a heat sensor of my (old) coolermaster aerogate on the side of tha flash drive and put in into a usb 3.0 port on the front of an icy box USB hub / card reader.

The sensor reached a temp of 55°C (131°f) max when reading or writing 40GB of data

Moving the flash drive to a USB 2 port didn’t change the temperature. About 2 degrees. But still very hot. Even using an USB2 extention cable with an “open” connector didn’t change anything.

sandisk ultrafit.png

Even when only idle in a USB port it was about 40-42°C

The idea of this type of flash drive is to keep in stationary in a device (it’s so small you will lose if it’s not permanently attached to something). But it is a battery drain! Tested it on a laptop an on my android tablet with an otg cable. On both of them it gets warm even when doing nothing.

OK it was cheap, but I have zero confidence in these flash drives. To be sure it won’t damage my TV I put it on a logitech extension piece from a unifying receiver. Beter be safe then sorry

@roadranger wrote:

I have a 32GB that seems to not overheat like my 128GB does. In any case the solution is simple - just use a USB2.0 port when writing large amounts data to it.

In that case, it defeats the purpose of buying a USB 3.0 flashdisk.

@chin wrote:

In that case, it defeats the purpose of buying a USB 3.0 flashdisk.

In my case I keep it plugged into a USB2.0 only device for music playback. While it would be nice to be able to wrte to it on a USB3.0 port I rarely do that now that I have it loaded up :slight_smile: .

Hi, I removed the plastik and metal casing and inserted it into a USB port but the Ultra fit wont work and its not recognized. I was hoping the heat can get away much better like that. Is there some ground not touching when naked without its metal housing? The pins on the USB seem to connect fine when inserted.

You understand the metal is what helps dissipate the heat, right? Removing it does more harm than good.

Mine Utra Fit 128Gb died (permanently gone to the read only state) after 11 month of work, very hot work. R.I.P.

(I posted a ‘solution’ earlier, but the links to the suggested cable, are now not supplying a suitable cable - fit is too loose )

Here is my solution -

Purchase an extension cable (Male and Female ends) that will help dissipate the heat. The female end has to have no rubber covering so that it is metal to metal and the metal is exposed to the air.

Also I (very much) like the female end to provide a VERY snug fit for the SanDisk thumb drive

This helps keep the heat manageable, and prevents any damage to the usb soclet on your laptop(etc)

I recently browsed eBay looking for a current sale that might match my requirements.

I just received one today and it is perfect.

Here is the link -


I just ordered another 6, so be quick (He is only showing 4 left)


negusp, that was not the question and I think no, the metal will not conduct the heat well.

The extension cable is not a solution. Why would I buy a miniature Usb device and attach a cord and an adapter, thats ridiculous. 

Is anyone able to make the naked board work in an USB slot?

The metal will conduct heat far better than using a naked board.

What do you think heatsinks do? They dissipate heat from the main board by spreading heat over a larger surface area. The metal is crucial in this.

That is exactly what the extension intends to do, but more effectively. A naked board is not an effective solution.