Lexar and a range of other USB flash drives have been tested by others, including this one:
https://ssd-tester.com/usb_flash_drive_test.php
or this one:
Their read/write speeds are not dissimilar to other known branded flash drives, and vary depending on the model tested.
Such websites are better than relying on consumer reviews for information as they are test results rather than opinions.
Comments on USB stick reliability seem to be on solid foundation although perhaps not with a totally broad brush.
I just returned to this thread and see my Dec 2023 reply was not posted. It’s in “draft” mode. So here it is:
No doubt there are countless possibilities to explain why a USB does not work when connected to a laptop via or not via a hub. Some folk have offered suggestions. Thanks.
I just encountered a nasty situation, possibly due to the USB’s original format of FAT32 which I have not changed.
Using the same USB with a mac and then using it in a pc (to download articles in a library) and then returning to use it with the mac resulted in the folder into which I thought I saved the article not only did not contain the article but when I tried to access that folder on the mac, the entire contents of that folder vanished.
This was very odd. Twice I ran antivirus scans at the library before and after downloading the article. No other file or folder on that USB disappeared and while I find the Lexar USB slow, it still works with the mac.
Update 14APR24
Earlier I mentioned the appalling unreliability of Lexar usb.
If I bought 1 or 2 I would not be so concerned, but I bought several and gave friends a few.
They were on sale at Harvey Norman a few months ago.
For the last month one 16GB Lexar worked well on mac and windows. The only downside I saw was the slow transfer rate, which is no big deal for me.
Last week I should have been more proactive and seen what’s coming: the usb was not detected by the macbook, so I had to unplug and re-plug it into the macbook before it was detected.
It then worked well.
Last night the usb was detected by the mac but not accessible. I could see no folders.
I tried to copy a folder into it (from the desktop) and while it took a long time, it appeared to have been copied successfully.
But after it appeared in the usb, as the only folder (when there should be dozens) it vanished.
The usb then showed no files or folders.
I could not eject the usb.
There were no applications at work, so I could not understand the error message about ejecting without addressing the program in use. In the end I had to Force Eject (which I know has risks). But what else could I do? Yanking the usb without properly ejecting or using Force Eject also comes with problems.
I then plugged the usb into the mac and while it was detected (I could see it on the desktop),
mac disk utility did not manage to “repair” the usb. In fact the usb was listed as “unmounted”. Trying to “mount” via disk utility failed.
Oddly disk utility indicated the disk was full with no free space. It showed 2.9GB used just prior to it failing.
In earlier falled Lexar usbs (note I bought several usbs in one go), disk utility showed no space used ie a blank usb.
Bottom line: playing the pokies will yield the same result as using a usb: money down the drain, but at least the pokies is so much more fun.
I learned my lesson from the first failed usb and the night before backed up the data on the second failed usb.
Lexar are a brand that is not considered cheap and nasty.
But, I do not buy any USB flash drives that are not to USB 3 compatibility. The slow write speed is due to drives being USB 2, I would guess.
If you want to use Fat32, then the limits apply. The hard limit is 4G per file, which is not enough for video.
Flash technology as used on these stick drives is not designed for lots of writes. They will wear out quickly.
Thanks for the feedback. The usb is now not even detected by the mac, where previously it was detected but not accessible.
Interesting what you wrote about the 4GB limit. I did not know that, but in any event, none of my files (which are articles or eBooks) come close to that.
Maybe I should try USB 3.0 as you mention. That said, all my USB 2.0 SanDisk usbs have over the years worked and still work flawlessly. In fact I have an old 1GB usb, also SanDisk, yes one GB and it works very well.
I will definitely bear in mind what you wrote about “lots of writes”. But I wonder, how many is “lots”? In my case, weekly I download 6-10 articles at a university or public library (as I cannot access them from my home or office), save them, print them and often delete them.
It’s not like I am a “heavy user”.
It could be one of your USB ports running at a voltage greater than 5V, rather than a problem with the flash drive.
As you have had multiple flash drives dying, it points towards a faulty USB port. Higher than 5V could be the culprit or a fault within the port corrupting the flash drives. It may be a faulty motherboard, connections/cabling etc within the computer.
USB 3.0 has been around for many years now, and whilst the primary difference is in transfer speed, USB 2.0 on cheaper devices just says older technology to me with the controller chips that handle the buffering and reads and writes, and monitoring of blocks of memory cells as they eventually fail and have to be reallocated.
Hard disk controllers do this detection and reallocation of bad sectors, as do today’s solid state hard drives.
Your usage of USB memory sticks is definitely not ‘lots’ of writes.
What I am thinking of is the situation where one might carry around a device with apps on it like your preferred browser or word processor and run those apps from the plugged in device. Such as if you frequented Internet cafes, or a workplace with locked-down computers.
So what happens if you just reformat the device to FAT32 to build a new directory?
A useful tool and one I use and recommend is Gparted. It is the Linux partition manager based on GNU Parted. This often allows me to fix drives that seemed otherwise unusable. It can be used in the live version on Windows and macOS.
What it can do is listed at the following link
https://gparted.org/features.php
While over voltage has been mentioned, there also needs the consideration that the power supplied via the USB port may be insufficient to properly run the inserted device and could cause failures.
Some mention of poor power supply on M1 chipped machines has been made on the Apple support site. I would usually expect that if too low powered that a below 4.75 V (5 V - 5%) warning would be provided, if marginally poor though this may not necessarily occur.
https://discussions.apple.com/thread/254277978?sortBy=best
Has a powered hub been considered? If it is possibly an issue of low power supply through the port or ports, then a powered hub can circumvent the issue. Ensuring there is enough power to write to the chips in the USB device can be critical, particularly when the FAT (file allocation table) is updated on the device. If the FAT becomes corrupted the device may no longer work as intended, it may show incorrect available space and used space. It may also not allow any further writes or reads to be made as the pointers may be corrupt.
For expected voltages available through the USB port, for USB 2 upper voltage is 5.25 V and the lower voltage is 4.75 V (5 V ± 5%) at 0.5 A. Voltage expected is the same for USB 3 and USB C. Amps however vary with the USB 3 and C standards with USB 3 having an expected 0.9 A or 4.5 Watts (1.5 A for dedicated charging port or 7.5 Watts), USB 3.1 having a maximum 3.0 A (though typically the same as 3.0) and USB-C (USB 3.2) is 3.0 A (15 Watts).
I believe on Apple devices that some directly connected Apple peripheral devices e.g. an iPhone can have more power delivered than the normal standards. I think on a standard USB 3.X port (not 3.2) it is 10.5 Watts. This would be software managed and if this control is somehow broken then perhaps low voltages and power output could happen, obviously ports can be powered down as part of the energy saving specs of the Macs as it is in other PCs.
Which is why I do this. To avoid possible power issues with say an external hard drive, or phone charging on the same port, which will have a higher current demand. Also avoiding the multiplexing of various data streams down one pair of wires.
You suggest reformatting the usb.
I understand that will delete the countless files I have on it, so that doesn’t make sense for me. My objective is to be able to ideally use the usb again for saving downloads or at the leat, to be able to access the usb one more time and verify what if anything I have to date not backed up.
Before attempting any of the following, I recommend that you use a powered hub to insert the USB drive/drives into. This will help ensure that the USB drives are receiving adequate power to operate properly.
Gparted has some ability to recover files from damaged partitions. With FAT32 partitions the tool can certainly attempt recovery. Not all partition types (file structures) can be e.g. apfs has some limitations about what can be done. My first step would be see if a sector by sector image of the drive could be created or a clone of the drive, from what you have indicated you can’t really access the drive so any backup may not be possible. Next would be to do a check of the drive and see if repairs can be done, this risks loss of data when/if repairs are undertaken so just check first. Then try recovery of data from any damaged partitions, if this is unsuccessful then try any possible repairs. If repairs fail then try reformatting the drive. Gparted may reformat drives when other normal utilities fail.
There are other recovery tools you may wish to try e.g. Recuva, MiniTools Power Data Recovery Free edition or the MiniTool Mac Data Recovery (limit of 1 GB of data allowed to be recovered with the free version), the Windows File Recovery app (no limit but it is command line usage so read the help section on Microsoft), Wise Data Recovery from WiseCleaner (2 GB limit for the free version and the paid for ones are expensive in my opinion), Puran File Recovery from Puran Software (it is an older program but still works well), PhotoRec (would normally not be my first choice), NCH Orion File Recovery (avoid the extra program installs it will try to put on your system). Some of these are able to be installed on Macs but most are Win type programs.
It would be necessary to copy the files elsewhere before doing a format. If these files are important you ought to keep backup copies in any case as any medium you have them on could fail at any time.
Yes, the rule of 3-2-1 is always the least that should be accepted as the procedure.
A bit of reading about this golden rule for anyone interested. Any business recommendations in the article are provided by the business and I make no recommendations about them.
@grahroll - thanks for the reply. You gave me much to consider.
@syncretic - the problem is I cannot copy from or back up the usb as it is either not detected by my mac or a pc OR it is detected but indicates there is no free space left on the usb while not revealing to me the files and folders on the usb.
Then try the repair utilities before the reformat, you may salvage something, as it is you have nothing so any files saved are a plus. After that a reformat might make the drive useful but no guarantees. Once you have as much as you can get set up a backup routine for the future.
A lesson I can relate from many years ago after a USB drive was accidentally flung across the room and landed hard on the concrete. No recovery as it was totally unresponsive. I recollect that many of the earlier reviews of USB and like flash drives included drop tests along with other reliability tests. Failures were often noted in the testing of most products.
Subsequent wisdom was to always save the initial copy of any file directly to the local drive of the PC, laptop etc. The file was subsequently copied in a seperate action onto a USB if required. Full knowledge is one does not know the version saved to the USB has been successfully saved until one tries to open it or copy it from the device. Considering one’s PC etc should also be frequently and independently backed up - there would be 2 alternate copies available at the end of each day?
Choice has some useful information on files/computer backups:
You are talking about two things here.
Try to access the files on the device to recover what you can to another place. That would require some sort of utility that could get past logical and physical problems with the file system. As others have said, there are quite a few available in addition to the ones that come with the OS.
If you want to continue to use the device, and it is phyically OK, then a full reformat as FAT32 will create a fresh file system. And yes, anything previously there will be gone for good.
FAT32 has some limitations on the way you use file system of your sticks. I don’t know what size USB sticks you are using but FAT32 only supports a cluster size of a maximum of 16 KB, so if a large drive of between 16 GB and 32 GB (this is the usual maximum size disk for FAT32) the cluster size will be 16 KB each, if 8 GB to 16 GB the cluster size will be 8 KB each This means that a 1 bit file (an absurd file size but used to illustrate the wastage) on a 32 GB stick, will use the 16 KB cluster to store that 1 bit of data. While FAT32 has a capacity of 4 GB per file just for comparison NTFS has a file size capacity of 256 TB and a maximum disk size of 256 TB. If FAT32 you won’t be able to format a drive bigger than 32 GB successfully unless you use a command line utility to do so and using the command line format will take a very long time to finish… If using the Win format tool it will fail on drives bigger than 32 GB with the following warning “Logical Disk Manager: Volume size too big”, you will need to partition it to use more than 32 GB of USB sticks larger than 32 GB. Another issue is the way the file names are stored, if using LFN (long file names) rather than solely SFN (short file names i.e., 8 characters for the file name plus the . and the extension) then FAT32 FATs will store both a LFN and a SFN and this will drastically reduce the number of files a FAT32 device can store (if only SFN then it is 4,117,920 files maximum per volume and in a folder it is a maximum of 65,534 files). There are other problems with FAT32 including the inability for the file system to self repair files.
exFAT may be a better choice of format, it is understood by macOS (both read and write) and Windows (it was a Microsoft development). 128 petabyte maximum file size, 128 petabyte maximum partition size ( one hundred and twenty five million gigabytes) this is because exFAT uses a 64 bit file system rather than a 32 bit one. exFAT has other pros, these include it was designed for the larger modern external drives, it reduces the number of reads and writes required compared to when NTFS is used, NTFS journaling reduces the lifespan of USB sticks and memory cards. exFAT also keeps a record of free and used clusters which helps speed up writing of files compared to FAT32, it does not store SFN and only uses LFN thus saving space used. If a exFAt partition gets damaged, then using the Disk Management tool to assign a new drive letter can work well, or using DiskPart to do the same., or using another partition management tool to assign a new drive letter. In regards to file recovery exFAt is not much different to FAT32, if you want more robustness then perhaps NTFS is a way to go (noting that the journaling will decrease the USB drives lifespan), as in Server 2008 ‘self healing NTFS’ was introduced to NTFS. This often obviates the need to run CHKDSK to carry out repairs. Another issue with NTFS is that macOS can read the files but third party tools are needed if wanting to write the files.
Importantly, exFAT drives still should be ‘ejected’ to reduce the risk of corruption, forced removal as with FAT32 can lead to file pointer corruption.
Loads of good info there. 
Really, the FAT file system is a historical hangover from the early days of MS DOS. Nothing much to recommend it today, except that pretty much every computer OS understands it. The lowest common denominator.
But, out of the pack, most flash drives have the FAT32 file system preformatted. Which just means a directory structure. With the rest of the space some random bunch of bits. Probably no full write/read test to identify bad parts of memory to block them off from use in file allocation.
A quick format rather than a full format. The latter checks every sector and flags bad ones as not to be used.
If I was considering using a USB flash device for anything other than a temporary storage mechanism to transfer files from one computer to another, where the files would then exist on both the source, and the target, then I would not care much.
But as a backup, reformat to the appropriate file system before use.
