when i connect my flash drive to my mac it doesn't come up to view or to even copy the files over.

Welcome to the Apple Support Communities

Probably your USB drive is detected, but you don't find it because the USB drive doesn't show up in Desktop. To access to the USB drive, open Finder (press the icon at the left of the Dock), and choose your USB drive in the Finder sidebar, under "Devices".

If you want to show your USB drive in Desktop, open Finder menu > Preferences > General, and tick "External disks"

At the left part of the Finder window, you will find its sidebar. Here, you should see a "Devices" list at the bottom of the sidebar. If you don't see it, scroll down, and finally, choose the USB drive.

To show it in Desktop, just go to the menu bar and press the "Finder" button, and then, select the "Preferences" option. Then, in the window you should see, tick "External disks", and the USB drive should appear in Desktop

You are welcome

I have no USB under devices…how do I make that happen?

thank you so much

Thank you. Now, if you could just help me get rid of the Firefox disk image that appears each time I open Firefox. I have gone to the Firefox Forum and read and re-read and followed the instructions, all to no avail. The Firefox disk image appears every time I open Firefox. I would use Safari instead, but Google Drive doesn't support OS 10.6, and I'm not a Chrome or Opera or IE fan.

MY USB is not coming up on the sidebar

You might want to consider starting a new discussion. Since this one is a couple of years old, less people are likely to look at it. A new post would be much more visible. You can link to this one.

It's because smth is wrong with the flash drive , try to reformat it on the windows computer , if it's "healthy " device , then it must be visible by mac