[File] cannot be opened for writing

You can check for the following:
Are you the owner of the files - add a column in the Eindows explorer for that. If you see a strange letter-number combination, then use Windows to become the owner.

If you experience the problem with longer files or especially with the files that the explorer shows while you edit them in MP3tag, then close the Explorer window.
If you have Windows Media player open at the same time as you edit the files, then close Windows Media player.

Also, the indexing for a drive could cause the access problems.
And: do not play a file while you edit it.

Again, thanks for your help. As soon as I ran into the problem again, I tested your suggestions systematically. First, let me add that the problem is usually limited to adding cover art, but sometimes I can't edit the tag at all.

I checked ownership, and I see no issues there.

On the first failure, I closed that explorer window for that folder (which I do always have open), and I was able to then add the cover art.

On the second failure, neither closing the explorer window nor closing WMP worked, as I was still unable to add cover art.

I do not attempt to edit tags while the file is being played, etc.

As a reminder, this is a new issue for me. I have had explorer windows and WMP open for as long as I have been using MP3Tag, and this issue just started a few months ago.

Another possible culprit may be the graphics driver. I have NVIDIA GeForce GT 720, and there seems to be an unusual number of updates recently. Plus the problem is typically with adding cover art.

Thanks for testing.
If you add cover art then the tag area usually has to be expanded as the cover most likely does not fit into the already existing padding for the tag. So the whole file gets rewritten, first to a tmp-file and then back to the original. If then some other program blocks the original file, you get the error message.

Anyway: this is not a problem originating in MP3tag, MP3tag is merely the messenger: the file is blocked.
You may now investigate what was changed in the meantime and particularly look for programs that are interested in media files - and run in the background.

In W7 there was e.g. the sidebar application for showing pictures. and this regularly blocked also music files ...

Okay, this problem persists and is getting worse. To further track it down, I have uninstalled the latest version and installed v2.78 to see if the issue is version specific on my computer. Now I find that all of the functions are greyed out except "Play". Any ideas?

Usually, you have to select at least one file in the files list.

Of course. I'm now trying v2.79 and getting the same issue. The program starts up fine, but I noticed that existing tags do not show cover art.

When I try to add some tag information to a file, the program essentially freezes. I have to abort the tag creation, resulting in all functions disabled except for play. I can't even close the program via the "X", having to use Task Manager. I have never experienced these additional issues until today.

You can filter for files that apparently have no covers:
%_covers% MISSING

If Mp3tag cannot write back the data (probably the padding is not large enough so the file has to be re-written with the detour of a tmp-file) and has problems due to local circumstances, you might see that behaviour.

So I still insist on you checking the access permissions for the audio files as well as the installation folder. It is usually not enough to have an administrator-like user but it is best if the MP3tag user is also the owner of the audio files.
If you install MP3tag with a different user-id than that which in the end modifies the files, you best run MP3tag as Administrator.
You have been a little vague about the whole business of access permissions and ownerships.

I can only recommend to use the MP3tag internal means to open files and not D&D them from the Windows Explorer or use the WE context menu. Alternatively, either close the Explorer window or navigate to a different location.

A glance at the services or something like that is probably not very helpful as you do not see that a particular file is actually being accessed. You would have to use a process explorer e.g. the one by Microsoft: https://technet.microsoft.com/en-us/sysinte...s/bb896645.aspx

As you see that different versions of MP3tag hardly make any difference, I would say, it is now time to do something about the environment on your machine. And the easiest part is to check access permissions and ownership. And close the WE.

After that it could be good idea to check the files for consistency with tools like MP3val, Mp3diags and/or Foobar2000.

Again, thanks for your assistance. I am the only person who uses this computer. The installer, user and administrator are all identical. I addressed ownership/permissions to the best of my ability during the earlier exchange. I have yet to use that link or other referenced tools. May try those next.

I did do some additional "testing". When I just load a folder/sub with far fewer files, the program seems to work as expected. The problems return when I load my entire library. This suggests that the program cannot handle this sized library and/or the computer is not allocating enough resources to the application.

I've now installed the latest version and will "run as administrator".

See this thread on possible memory problems:
/t/16790/1

There is no library in MP3Tag. The content of the tags are read while loading and keep in memory.
As a 32 bit program MP3Tag is only able to use up to about 3,5 GB of memory, if you keep a lot of software in your memory even less. The affordable memory depends on the amount of tags that are in your music-files.

But anyway up to about 50.000 music files should be no problem.

Sorry for misusing a term of art (i.e. "library"), as I was unaware. I was referencing my personal pool of audio files. Nevertheless, the cause of my problems seems to have been identified. I have over 65K audio files, allocated to different sub-folders for better organization. To test further I just added each sub-folder separately, and the issue resurfaced somewhere between ~52K - 69K files.

Going back to the start of my problems, as more files were added to the pool, the initial cover art barrier started to arise and only got worse as the pool got larger and larger. Originally, rebooting, etc. resolved the problem (i.e. clearing out the memory), but this no longer works.

To resolve the issue, I have now moved some lower priority sub-folders and am currently retesting. I will attempt a work around by running the program on a second desktop within Win10 to handle the low priority files.

Update: Unfortunately, it appears that I've passed the limit that the program can currently handle. After moving low-priority files and loading the smaller, but essential pool, the problems persist. Looks like I will have to find another software option, which I do not want to do. I have been happy with mpetag thus far, and would continue to recommend for people with a more typical number of files.

Hopefully, this issue will be resolved with a future version.

Although it may not be possible to load all the files in most cases I see no necessarity for this.
I think it is very seldom necessary to have all files in memory and perform actions on all of them.

The dayly work is more to add new albums and tag them properly.
If someone has more than 50.000 files and wants to load them everytime in MP3Tag to my opinion it takes much too long.
The only case when I miss this abliity is when I make am export-list of all my files but even then it is no real problem to first load artists a-m and then maybe n-z and put the ouput together in one file.

I suppose we all have different needs. For my purposes, I need all loaded. I really prefer the mp3tag feel and interface to other options that I have tried over the years. I'm sure eventually a future version will overcome this barrier.

UPDATE:

As a recap, I was reluctantly forced to switch to another tag editor due to memory issues with so many files.

One if the features of the new editor is that it will list all of the different cover art images when editing a batch (e.g. an entire album). This allows me to edit a batch to the same image. (This is a feature that should be considered for future versions of MP3Tag.)

Due to this feature, I started a project to clean-up the cover art images. After editing a large number of files, I opened MP3Tag to see if the original problems persisted, and they do not. This tells me that the deleted "extra" images freed up lots of memory for the editor.

I also noticed that MP3Tag reads some dates as (for example) "2014\\2014" after some recent tag edits, which I have also seen after Audacity edits. This suggests some compatibility issues.

Note that when I right-click an image within MP3Tag and copy to another file, the two cover art images are not digitally identical.

Since I would eventually like to return to MP3Tag, I wanted to provide this follow-up and related observations.

MP3tag shows the contents of multi-value fields.
Apparently you got at least 2 YEAR fields. Check the extended tags dialogue.
Where do you see the compatibility issues?

Also, you can watch the task manager to see how much memory is still available.
Just as a reminder: MP3tag is a program for tagging and no administration program for a collection.
So just load those files that need tagging and those that you need for reference. I doubt that this must be all.

Tag anomaly

First, thanks for the continued interest in this thread.

Second, why would Media Monkey and Audacity add a 2nd year field, resulting in the "2017//2017"? That is why I suggested compatibility issues, tho I assume that I am missing the term.

Third, as noted earlier, my purposes require loading all files. MP3Tag currently lists all of the various fields' populations as dropdown options when editing a batch, except for the cover art. I find this feature very helpful when cleaning up typos, etc. I am simply suggesting that this feature be extended to cover art in future versions.

It's just a different opinion of what is standard.

Good question. Have you asked in their forums?
If you follow the link provided by user poster, you will see that MM maps certain other fields to year. And perhaps they don't want to loose any data and create a second YEAR field ...
As MP3tag accurately displays even the second (or more) YEAR field, I do not see any compatibility problems. I do see implementation problems on the side of the other programs.

What I don't understand: you ran into tagging problems because you reached the memory limit and it is still not possible to think of a different workflow?

Did you know that it is possible to d&d files from iTunes directly into MP3tag for editing? With (just as an example) iTunes as the administration program for the whole collection you could pinpoint exactly those files that are necessary to perform your current task. So you might save the MP3tag features and still access your whole collection.

Haven't asked in their forums as I'm new to MM and just noticed the issue when I retested Mp3tag and Audacity is not a primarily a tag editor. It would appear to me that MM and Audacity see the same year field, with Mp3tag being the odd one out, tho perhaps if we considered more programs, the majority vote would come out differently.

I use iTunes for adding lyrics, but I don't like its interface and options for other tag edits. My workflow is the dog here, not the tail.

Again, my recent comments are designed to suggest improvements to Mp3tag, as I hope to come back to it in the future. We can always learn from how others do things.