When copying large files, the progress bar suddenly freezes for a few seconds before continuing.

Hi — a short pause near the end can be normal because Explorer may have finished reading the file but is still flushing cached data, updating metadata, or waiting for the destination drive to confirm the write. That is why it can sit at 90% and then jump to complete.

Since you see it with different drives and ports, I’d test one large file with `robocopy` from Terminal. If Robocopy pauses too, watch Disk activity in Task Manager or Resource Monitor during the pause and run the drive maker’s health test plus `chkdsk /scan`. If only Explorer pauses, restart Windows Explorer and temporarily disable non-Microsoft shell extensions or antivirus scanning to test for a hook delaying completion.

Please don’t unplug the drive while it is paused—the final cache flush may still be running. Roughly how large are the files, and are the source and destination NTFS, exFAT, USB, or network storage?