New Macbook Pro M4 won't recognize external hard drive

roko92 wrote:

Finally external hard drive magically appear, not sure how I didn't change any specific system settings

There may be a problem with that external drive:

• It connected as a USB 2 device, that's anomalous
• It did not mount for a long time -- that indicates that your Mac detected a problem and tried to run fsck internally to repair it, which can take a long time (minutes to more than an hour).
• While the drive is in an unmounted state and your system is running fsck, Disk Utility may appear to be hung or suspended, which you also witnessed
• You mounted the drive on a Linux PC which is fine but it should mount on Macs and PCs properly and it did not.
• You could try copying all files off the drive to a safe place and then erase/format it to GUID/APFS format and see if it behaves normally. If you need to use it on a PC also you can format it as ExFat after this test with GUID/APFS. However I would personally not trust the drive anymore if it were mine.

Your screenshot from System Profiler is showing the SanDisk drive is only connected as a USB2 device which would make performance extremely slow. Try using another USB-C cable.

Also, try connecting the drive directly the computer. If you have the drive connected directly to the computer, then try using a good brand of USB3 powered hub or dock to see if that makes any difference.

roko92 wrote:

Hmm on which screenshot and under what property did you see that drive is connected as USB2 device?

You only have one screenshot showing the System Profiler (it is the first/top one). The other two are showing the Finder Settings and Disk Utility. I highlighted the area within the screenshot of the System Profiler which is showing your SanDisk drive is connected at 480Mb/s which is the max speed for USB2.

I connected it with original USB-C that came with hard drive, also i tried connect it with different USB-C cable. I'm pretty sure that cable is not problem because I connected same external hard drive with those cables to both Ubuntu (linux), Windows OS and old Macbook Pro M1 and all systems could recognize hard drive.

Unless you purchased & used a good high quality USB-C cable, it can still be an issue with the cable. The cables provided by the device manufacturers are usually just barely enough to work, but when you have issues it is best to use a high end cable so you can eliminate the cable as the problem.

And like @steve626 mentions, the SanDisk drive itself could be having issues....or even just the file system on that drive. You most likely have a hardware issue of some sort, or possibly the file system on the SanDisk drive is corrupt.

Plus the screenshot of the System Profiler is showing the SanDisk requires 500mA which is the maximum amount that is being provided to the drive so you are riding the line on having enough power for that drive. USB3 allows for more power than USB2.

It must be something with new Macbook Pro M4.

Each OS has slightly different tolerances for issues. macOS doesn't tolerate any imperfections unlike Windows & Linux which are usually better able to handle unexpected situations.

Currently I don't have and USB3 hub but will try to borrow some from friend and check it.

Let us know how that works out.

If you want to check the health of the SanDisk drive, then you can try running DriveDx (free trial period) and posting the complete text report here using the "Additional Text" icon which looks like a piece of paper on the forum editing toolbar. In order to attempt to check the health of an external USB drive, you will need to install a special USB driver.

that drive does appear to be recognized, and its partitioning information can be accessed, according to your system report.

It is named disk6 and is exFAT format.

please post the results of the terminal command:

diskutil list

¿what version MacOS?

You can plug in the external and shutdown and restart the Mac and see if it registers

>Shut Down... Restart and compare your results.

To be proactive you can file a bug report / submit your Apple Feedback here: Product Feedback - Apple

you can wait for point-updates to roll out to sort known issue with the new macOS 26

From the Terminal.app copy and paste: