This is going to be a long post and this happened months back. I previously asked this on Reddit but I felt unsatisfied with the responses. This'll be a copy and paste from there with some minor edits.
So I was trying to transfer some files on my Mac to my SanDisk 256GB Cruzer USB 2.0 Flash Drive - SDCZ36-256G-B35 and as I waited for the files to transfer I decided to watch some videos to occupy myself in the mean time. In the past whenever I'm watching videos or just browsing on Firefox as I'm transferring files it seems to affect the file transfers and stops it and gives me an unexpected error occurred message. It didn't seem to affect anything so I didn't think much of it and will usually just transfer the files again and it works the second time. Usually I'll keep my computer usage to a minimum for the second transfer and the file transfers work successfully. But on occasion as soon as I'm done with the file transfers and go to eject the thumbdrive it'll give me the message that the thumbdrive is in use and will be unable to eject. It gives me a force eject option, but I never click on it and instead will try to click cancel. But the message will soon disappear along with the thumbdrive icon before I get the chance to click "cancel" so I assume that it ejected as normal and I never needed to worry about pulling the thumbdrive out.
But today something different happened. Once again I got the unexpected error occurred message and tried a second transfer. But this time instead of prompting me to stop, replace, or merge my folders I instead got message that didn't include the merge option. It only told me to either stop or replace the file because the folder already exists. I thought it was weird and decided to click cancel so I wouldn't mess with anything. I go to click on my Finder and my Thumbdrive now shows up as completely empty. However, it still indicates that the storage space has been used. It is a 256GB SanDisk thumbdrive and currently I have 47GB available to use. I went to disk utility and attempted a first aid repair but I get an error message saying this: [Repairing file system. Volume could not be unmounted. Restoring the original state found as mounted. Unable to unmount volume for repair. Operation failed...] I've also tried ejecting it but it prevents me from doing so and I cancel the ejection. I have done nothing else other than a relaunch of the Finder. And just as I was typing this up, the thumbdrive seemed to have ejected and Mac gives me an error message that the SanDisk was ejected improperly. I haven't attempted an ejection in the last 20 minutes. It seems like the ejection was delayed. But since my Mac treated it as an ejection I unplugged my thumbdrive and plugged it back in, hoping that my computer was just being slow and that was the reason why my thumbdrive couldn't be repaired because it was in the middle of being ejected. But now it seems like my Mac doesn't even acknowledge that my Thumbdrive has been plugged. I even tried logging out and logging back in in hopes that it'll show up on my Finder's side bar and nothing. There's no greyed out option or anything on the sidebar. My other thumbdrives work but not this one. I've also noticed the past two times I used my thumbdrive my files had been transferring much faster than the usual hour that it takes. So it sounds as though my thumbdrive was corrupted but I have no idea what was done wrong to corrupt it.
Newer information: my 32GB SanDisk thumbdrive is now experiencing something similar where as soon as files are done transferring and I attempt to eject, I'll get the force eject prompt but before I either get a chance to click on it or even clicking "cancel" the message will disappear and it'll say that it has been ejected. Recently I've decided to play it safe and now only eject after logging off my Mac. I also bought a second 256GB SanDisk drive, the exact same as Amazon gave me the option to buy it again. This time the new thumbdrive came with installing instructions which I have been unable to do and my Mac stops recognizing it after plugging it in a few times. I have since returned it.
When I posted this on reddit I was suggested to plug my drives into a Windows or Linux but I do not own any and haven't since Windows Vista was a thing. I'd like to know what could be causing these issues before I go buy a different brand of thumbdrive or other external hard drives.
So I was trying to transfer some files on my Mac to my SanDisk 256GB Cruzer USB 2.0 Flash Drive - SDCZ36-256G-B35 and as I waited for the files to transfer I decided to watch some videos to occupy myself in the mean time. In the past whenever I'm watching videos or just browsing on Firefox as I'm transferring files it seems to affect the file transfers and stops it and gives me an unexpected error occurred message. It didn't seem to affect anything so I didn't think much of it and will usually just transfer the files again and it works the second time. Usually I'll keep my computer usage to a minimum for the second transfer and the file transfers work successfully. But on occasion as soon as I'm done with the file transfers and go to eject the thumbdrive it'll give me the message that the thumbdrive is in use and will be unable to eject. It gives me a force eject option, but I never click on it and instead will try to click cancel. But the message will soon disappear along with the thumbdrive icon before I get the chance to click "cancel" so I assume that it ejected as normal and I never needed to worry about pulling the thumbdrive out.
But today something different happened. Once again I got the unexpected error occurred message and tried a second transfer. But this time instead of prompting me to stop, replace, or merge my folders I instead got message that didn't include the merge option. It only told me to either stop or replace the file because the folder already exists. I thought it was weird and decided to click cancel so I wouldn't mess with anything. I go to click on my Finder and my Thumbdrive now shows up as completely empty. However, it still indicates that the storage space has been used. It is a 256GB SanDisk thumbdrive and currently I have 47GB available to use. I went to disk utility and attempted a first aid repair but I get an error message saying this: [Repairing file system. Volume could not be unmounted. Restoring the original state found as mounted. Unable to unmount volume for repair. Operation failed...] I've also tried ejecting it but it prevents me from doing so and I cancel the ejection. I have done nothing else other than a relaunch of the Finder. And just as I was typing this up, the thumbdrive seemed to have ejected and Mac gives me an error message that the SanDisk was ejected improperly. I haven't attempted an ejection in the last 20 minutes. It seems like the ejection was delayed. But since my Mac treated it as an ejection I unplugged my thumbdrive and plugged it back in, hoping that my computer was just being slow and that was the reason why my thumbdrive couldn't be repaired because it was in the middle of being ejected. But now it seems like my Mac doesn't even acknowledge that my Thumbdrive has been plugged. I even tried logging out and logging back in in hopes that it'll show up on my Finder's side bar and nothing. There's no greyed out option or anything on the sidebar. My other thumbdrives work but not this one. I've also noticed the past two times I used my thumbdrive my files had been transferring much faster than the usual hour that it takes. So it sounds as though my thumbdrive was corrupted but I have no idea what was done wrong to corrupt it.
Newer information: my 32GB SanDisk thumbdrive is now experiencing something similar where as soon as files are done transferring and I attempt to eject, I'll get the force eject prompt but before I either get a chance to click on it or even clicking "cancel" the message will disappear and it'll say that it has been ejected. Recently I've decided to play it safe and now only eject after logging off my Mac. I also bought a second 256GB SanDisk drive, the exact same as Amazon gave me the option to buy it again. This time the new thumbdrive came with installing instructions which I have been unable to do and my Mac stops recognizing it after plugging it in a few times. I have since returned it.
When I posted this on reddit I was suggested to plug my drives into a Windows or Linux but I do not own any and haven't since Windows Vista was a thing. I'd like to know what could be causing these issues before I go buy a different brand of thumbdrive or other external hard drives.
