HT

Copy the file(s), then hold CMD key (or is it Opt?, sorry, I now do it from muscle memory) when pasting and OSX offers the option to Move instead of copying the file.

HT

Every chance your TIFF file busts the file size limit on your external drive.

If it is formatted to FAT16 or FAT32 or some variation thereof, and your a regular TIFF file (or PSD) user, you probably should reformat the disk to NTFS or even better, if you use Mac exclusively, HFS (Journaled) to put large files such as TIFF and PSD onto that drive.

As a matter of course, it’s generally better to reformat an external drive upon purchase to your computers native file system anyway.

Edit: simplified my answer.

a6k Loc: Detroit & Sanibel

Correct. Cmd V + Option key after a copy operation. Not a visible choice like with a right click. Will do the move either to same or different volume. Now you went and gave away the message inside the secret decoder ring. Darn.

smussler Loc: Land O Lakes, FL - Formerly Miller Place, NY

Before sending my response, to verify what I was saying, I moved a read-only file between drives (Win-10) After moving the file to the target drive, Win-10 did delete the original from the source drive. Right Click was used (actually can not think of another way to move file between drives). If you left click and drag the file from one drive to another, then a copy remains on both drives. Left click and drag a file from one folder to another on the same drive, then it is "moved" - leaving one copy on the drive. I seem to remember being able to "lock" files, but maybe that was in "PRO" versions of Windows - used to use in work, 10 years back now . . . Windows NT - I think.

Manglesphoto Loc: 70 miles south of St.Louis

The OP is working with an iMac not a win10 pc

a6k Loc: Detroit & Sanibel

Well meant, I'm sure. But formatting the drive to NTFS for a Mac is not ideal since then one would need either a Windows PC, a 3rd party app for the Mac or to have the external drive on a network. Macs don't natively work well with NTFS.

HT

Yeah, that’s what happens occasionally when you answer questions on an iPhone waiting the Mrs to finish shopping.

Still, the OP’s core problem is most likely the file size exceeds the current format system used on his/her external drive. Since the OP is using a Mac, and if file size is actually the problem, then either store the file elsewhere or reformat the disk in Mac OS Extended or other format system capable of handling 4Gb + file sizes.

HT

Yeah, so many useful shortcuts not listed in the menus. One must almost become an OSX Ninja (same for LR, so many functions without any obvious menu access).

I miss the ease and completely intuitive use of apps (is that the right word for an executable file these days) like GNU and vi 🙄

a6k Loc: Detroit & Sanibel

HT wrote: Yeah, so many useful shortcuts not listed in the menus. One must almost become an OSX Ninja (same for LR, so many functions without any obvious menu access).

I miss the ease and completely intuitive use of apps (is that the right word for an executable file these days) like GNU and vi 🙄--end quote

I have sometimes found good 1-page cheat sheets. https://macmost.com/images/posts/MacMostKeyboardShortcutsCatalina.jpg

A while back I was teaching Windows 7 to "seniors" and at that time my rule was "right click it". IMO, Win7 was the absolute best OS human interface (AKA GUI). I love my Mac but 7 was the best for teaching and for consistency. Sure, there were all sorts of key-stroke combos in that, too. But you didn't need them. Ten is a mess IMHO.

My iPhone to which I am surgically attached, is simply awful for non-intuitive user interaction. From what I've seen of my wife's Android, it's exponentially worse. There is no good option.

Apple keeps making good stuff not as good. I wonder what gets into them. Example: the MacOS Mail app won't let me define and size the columns any more. WTF?

This is my way of agreeing with you even though I'm not a GNU/vi user.

btw, I've easily put >1GB files on external drives. If that is the OP's problem it would have to be FAT16, wouldn't it? I have not see a TIFF that big, let alone 4GB.

HT

Not hard at all for TIFF Files to grow 4Gb+. I once managed a Print Shop (including printing maps, huge files!). But even for photographers, especially those new to TIFF, overlays etc.

I just suggest the OP look at file size since his 1.) using an external disk (likely a FAT file system) and 2.) their desire to work in TIFF, probably the fattest file format one can choose.

It’s not beyond reason to look at non obvious explanations when the obvious has already been explored 😎 Photoshop does, after all, provide for a Large Document Format for a reason...

Kind Regards

HT

FAT 16 - 2Gb file size limit
FAT 32 - 4Gb file size limit
NTFS - No practical limit, something like 8 Petabytes. Maybe an issue for the NSA or someone, but really...
NFS+ - No practical limit, massive files, a number so big I can't even comprehend it.

Larry Powell Loc: Columbus OH

There is no reason it will not let you do that. I do not have that problem on any of my Macs. Can you move a jpeg? Should be the same. You should be able to open a folder on the external and highlight and drag to that folder.

What is actually happening? Are you getting any messages?

LP

smussler Loc: Land O Lakes, FL - Formerly Miller Place, NY

I realize that. If the destination disk is full, either OS will give the type of error that he's seeing.

Larry Powell Loc: Columbus OH

I just moved to tif files between my boot drive and an external drive with no problem. In one case I dragged a file. In another, I did edit copy. I have a MacBook Pro 2019 running Catalina 10.15. I even went to Get Info and clicked on lock. The file dragged to the other drive.

I cannot answer your question other than guess the file is corrupt, but I would still expect it to move or copy. Try to duplicate the file and take it to the external drive.

The way the drive is formatted has nothing to do with this. Macs do not format like Windows. Good luck.

Larry Powell Loc: Columbus OH

See if this helps. Is is from Apple Help


If you can’t move or copy a file or folder on Mac
If you can’t move or copy an item, you might need to change its permissions settings. You might also need to change permissions settings for the disk, server, or folder where you want to move the item.

On your Mac, select the item, then choose File > Get Info, or press Command-I.

Click the disclosure triangle next to Sharing & Permissions to expand the section.

Click the pop-up menu next to your user name to see the permissions settings.

If you’re not logged in as an administrator, you may need to click the lock icon and enter an administrator name and password.

Change the permissions to either Read & Write or “Read only.”

If you need to, also change the permissions for the location where you want to put the item.