External disks become read-only after computer sleep

[MLGochnauer]

MacBook Pro Retina late 2013, macOS 10.12.6

Frequently (but not always) external hard disks on USB3.0 become read-only after the computer is reawakened (lid opened after a few minutes or hours). This is most likely to happen with SSD's, but also occurs with regular hard disks. The frequency seems to vary with the drive involved, but all are USB3.0.

I have not experimented with Thunderbolt drives to see if they have the problem too.

This wouldn't be too bad if ejecting and then reconnecting the drive(s) made them read/write again, but it doesn't. When they are reconnected I get an error message saying, "macOS can’t repair the disk..." As the message goes on to say, I can read and copy files from the disk but not write to it. The error message recommends backing up the data and reformatting the disk.

Restarting the computer with the disk attached has always solved the problem, but it seems diagnostic that macOS sees the disk as *damaged*, and not just read-only.

Does anyone know what is happening? It behaves as though something is not set properly when the computer goes to sleep, and so the OS misreads the resulting condition of drive access when it wakes up. Perhaps there is a way to force a 're-connect from zero' for the drive...??

Myron

 

[honestone]

What brand of external drives/SSDs are they? I have two external 512 gig Samsung 850 Pro SSDs, enclosed in Orico external enclosures, and no matter which of my Macs they are connected to via USB 3.0 (late 2012 Mac Mini, or mid 2013 13" MacBook Air), they work fine, whether I am reading, copying, or writing "stuff" to them. I am also using the latest Mac OS, OS 10.12.6, on both machines.

Not sure if it makes much difference, but both of those SSDs are about 6 months old.

Besides Disk Utility, do you have a more robust disk cleanup/maintenance/repair program, like Disk Warrior or Tech Tool Pro? If so, you could try to use either of them to analyze the external drives.

Finally, when restarting your machine makes everything OK, do you have enough room on either external drive to copy stuff from one drive to the other (on a separate partition would be best), then Erase and Format the drive you copied stuff from, and then copy stuff back to it? You can then do the same thing vice versa.

 

[MLGochnauer]

> What brand of external drives/SSDs are they?

The problem has occurred with a Samsung 1TB T3 (a few months old), a Toshiba 1TB HD in a Verbatim enclosure, and a "diskGO" enclosed Samsung EVO (?) 850 (less than a year old).

>I have two external 512 gig Samsung 850 Pro SSDs, enclosed in Orico external enclosures...

I used to have problems with Orico enclosed Samsung drives disconnecting, but I think that was a cabling problem. I epoxy the USB 3.0 cables to some of the enclosures now to keep them secure.

>Besides Disk Utility, do you have a more robust disk cleanup/maintenance/repair program...
I've used Drive Genius 4 on these drives, and they check out fine. I don't think the drives are defective in any way.

>Finally, ... Erase and Format...
I could do this, but it just seems like asking for trouble when it seems to be a software issue.

I just noticed that all three of the drives I mentioned above were formatted as EXTENDED FAT (XFAT). Perhaps that is the problem. I never used it until about a year ago. Perhaps I'll reformat one of the drives and see if it stops acting up.

 

[honestone]

What have you been placing on those drives? Given they are formatted as XFAT, not sure how you would read/process/write Mac "files" on them.

Why didn't you Erase and Format the drives, via Disk Utility, when you first got them? I always do that with new drives, as leaving them formatted for Windows OS use is worthless to me.

 

[MLGochnauer]

My understanding and experience is that macOS works perfectly well with exFAT drives (sorry for the misspelling earlier in this thread). It is certainly one of the formats Disk Utility can create. NTFS is certainly a problem, since Macs don't write that format, so I always reformat drives that come that way.

I started using exFAT because it made for easier exchange of files with a friend using non-Apple systems.

I was/am planning to use whatever new file system Mac is supposed to be coming out with. There is something new coming soon, isn't there?

 

[honestone]

When you say "macOS works perfectly well with exFAT drives", that is true for reading, processing, and in most cases writing files. However, as to whether those files can be read by a Windows machine is another matter. That would depend on the type of file written. For example, one of my flash drives is formatted as ExFAT, as I need that format to view movies/TV series on our Samsung 65" Smart TV. However, I can stick that flash drive into one of my USB 3.0 ports, launch VLC media player, select a movie/TV series from the flash drive, and it will play just fine.

On the other hand, there are some Mac apps that can only generate "Mac only" files. While one might be able to place them on a Windows-formatted device, I suspect such "Mac only" files, in most cases, cannot be read by any Windows apps.

The one Mac app I have that will generate "Mac only" files, but which can be read on Windows machines, is Office 2016. Of course, the Windows machine would need to have the Windows Version of the Office suite to process them.

Apple will be changing the "Finder File System" in High Sierra, but I have not seen any details about it, especially in regards to Windows systems. For such file exchanges, do you need all 3 drives formatted as ExFAT?

 

[MLGochnauer]

Do I need ExFAT for three drives? No. Unfortunately, my friend died of pancreatic cancer and I don't need it at all. But it seemed harmless enough for what I save: mostly raw image files, m4a music files and biggish TIF files, with the occasional rtf or pfd file thrown it. I never, ever expect a Microsoft product to cope with Pages, Mellel, XyWrite, Nota Bene or any number of other interesting file formats.

But the bottom line is: If my initial problem of drives suddenly becoming read-only after OS sleep is a result of the drives being ExFAT formatted, then there is an OS bug. I am not asking the system to do anything it hasn't purported to do for several years.

 

[honestone]

Do I need ExFAT for three drives? No. Unfortunately, my friend died of pancreatic cancer and I don't need it at all. But it seemed harmless enough for what I save: mostly raw image files, m4a music files and biggish TIF files, with the occasional rtf or pfd file thrown it. I never, ever expect a Microsoft product to cope with Pages, Mellel, XyWrite, Nota Bene or any number of other interesting file formats.

But the bottom line is: If my initial problem of drives suddenly becoming read-only after OS sleep is a result of the drives being ExFAT formatted, then there is an OS bug. I am not asking the system to do anything it hasn't purported to do for several years.

So, you need all of those drives for storing that stuff? That seems like a lot.

As for this sleep "issue", I guess there is a possible OS bug, but I suspect it is not a "prevalent" one, ie, not raised by a number of folks.