External USB need Repair on every cable insert

[Mac2013orlater]

External USB need Repair on every cable insert
An external USB storage is used. It is a 2.5 inch SATA hdd along with SATA-USB 3.0 adapter. GPT with two data partitions, one in FAT, another in Mac OS file system.
That one in Mac OS file system is used as second/alternate target for Time Machine Backups.
Before the TM backup process is started the Verify is made for
HDD and the Mac OS file system partition - manual start.
The made observations are that after every usb cable pull and
plug-in the Verify does not succeed and completes with recommendation to
make Repair.

In the fact it is sufficient after successful usage (here the TM backup) to pull the usb cable and after few seconds to plug in it back in order to run onto effect as described above.

Is this a sign of abnormal behavior? Something to be trouble-shoted?

 

[old-wiz]

are you ejecting the disk before pulling the cable? If not you are asking for trouble.

 

[Mac2013orlater]

are you ejecting the disk before pulling the cable? If not you are asking for trouble.

Sure!!!
Unmounting all partitions and ejecting the disk!

 

[old-wiz]

Hmm.. I have a couple of USB drives on Mavericks and mount/dismount with no issue. However, I don't have time machine running (I use clone backups). I wonder if having Time Machine on the drive makes a difference?

 

[Mac2013orlater]

In case of this external usb these are rare cases the Disk Utility succeeds on Verify and do not recommend Repair in order to complete partition of Mac OS file system verification.
It suffices to disconnect USB and after 1, or 2 seconds to plug it again in order to run into the described phenomenon.
This external is used for off-side backups, means it will be transported over distance of several miles on each usage, so I guessed initially these are shocks during transport what can lead to theses effects. However, the disk is in a shock absorbing case, actually two such cases as sandwich. Furthermore the made observation that disconnect and immediate reinsert of usb cable suffice is a sign that's not problem of shocks during transport.
However, it is not a classic external usb. It's 2.5 inch internal in shock-absorbing cases and SATA-USB-3.0 adapter. I hope the reason is not in this region.

Disk is formatted to GPT with two partitions. One in Mac OS without Journaling
in the most first sections of disk and with size of 140GB. Second partition is FAT32 in the end section of disk. Between them two approx 120GB unused space. That FAT32 one does never make such problems.