Peter

BCPL was a bit earlier than that. It was in use at Oxford in 1968 for what was then OS/1 (if I remember correctly) on a Modular-One computer. OS/6 was after my time there 1968-71). I don't know exactly when it was designed, but it was a cut-down version of CPL (Cambridge/Combined/Common/Chris's Programming Language) without typed variables.

Sorted now and self-answered (not to @Peregrino69's satisfaction).

@Bob OK Will do.

@AndrewMorton Nice idea, but I found there aren't any junctions or symlinks in the D: root directory.

@Peregrino69 Sorry for the incorrect etiquette - I'm not a frequent user of SuperUser. attrib works fine on C: but not on D: for reasons I don't understand. I'm getting the nasty feeling that there's a disk corruption. Worrying.

Further interesting information: I've run WinDirStat in 3 modes: logged in as admin, logged in as a user, and running as admin while logged in as user. And get 3 different results for the size of the unknown file: 142.7GB, 70.5GB and 738MB respectively. It looks as if there are files there which have different owners and so give different total sizes - but I thought that admin accounts had access to all files.

@Moab I've added a screenshot to my original question - it might help.

@Peregrino69 I don't see how attrib can help - it need a file name to work on. Using it without a file name comes up with D:\>attrib File not found - D:\*.*

@Moab The name comes up as <unknown>! Not a lot of help.

@harrymc I already tried that - see my original question.

@user1292580 I think I see what you mean - I used WinDirStat to find out what was taking up so much space. It comes up with a 70GB file <unknown>. Macrium backup tells me (using the total amount backed up) that it's backing it up. File explorer and dir command don't mention it at all. I'll be offline now until tomorrow.

@Peregrino69 I've tried that - it was actually WinDirStat which showed me what was taking so much space. But the right-click has that option greyed out, presumably because it's not a regular file. Or something..

@user1292580 Hint in what form? How can I find the GUID? Can you give me a hint??

@Bob Take your point about WDS being read-only. I now see why i got 3 different answers to the various ways of running it. The basic problem was that having cloned a disk from another system, the ownership and permissions got screwed. I only realised this when I started poking about and comparing output from WizTree with WDS.

By the way, WDS showed the folders as being empty. Now I've changed the permissions there's data in them. It's annoying that WDS, even when run as admin, doesn't find al the files.

I didn't try browsing them until I changed the folder's access rights. You're right about it being a dupe. I've self-answered anyway as you may find out when morning comes.

@Bob Aha! I've found it! There were some files which came from a cloned disk and didn't have any known owner on this system. I've now made them readable by myself and the <unknown> in WDS is now down to 2.6GB. As they're files that I want backed up I'm going to have to rework my backup strategy.... The fact that it's the same size as my 'Documents folder' was, it seems, a coincidence. Thanks for all the help.

I might have worked out some of the issue: the <unknown> size is just about the same size as my 'Documents' folder. I have to go now and won't be back until about 3:00 UK time. If you're in Australia I assume you'll have gone to bed by then.

But it doesn't back up unused space.

Image

Or did you mean the ways I ran WDS?

Not sure what you mean by 'modes'?

@Bob So is Macrium backup - it's backing something up which I probably don't want. That's why I asked the question.

@Bob WinDirStat gives 3 total sizes: running as admin it's 550.6GB, logged in as myself (user) it's 181.4GB, logged in as myself but running as admin it's 181.4GB. WizTree gives 181.4GB. Explorer gives 182GB used so that's OK. I ran chkdsk without any options. It says there's 209240264KB which is about 181.4GB so the numbers there seem right.

But there's nothing there which is taking up space. it says that the total size is 181.4GB and there aren't any unaccounted-for files (a few system files which WDS doesn't tell you about). So it seems that Macrium backup and WDS are seeing things that WizTree and Explorer don't. I tried running WizTree as an Admin but got the same result.

Well, I've now run WizTree - thanks for telling me about it. It's certainly quicker than WinDirStat!

It takes a bit of time to organise - I'm 'just about to install it. I'm not always at my desk!

@Bob I'm here now