Collage still does not work

1. Should I leave all the existing image files where they are and just start a new folder closer to the root for new downloads and edits?

Or

2. Should I move the entire Picture folder to a place one notch down from the root? If so, what is the best way to do that without screwing things up?

1. Which is better to do, 1. or 2., or does it not matter?

Choice 1 does not help much and 2 is not what I advise. You don't move the 'Pictures' folder which is special folder dedicated by Windows to your pictures and which has special properties working with other programs. You move the contents of the 'Pictures' folder to another folder, which has none of the special properties (acting as a shortcut in the Explorer for instance). If you have created another folder also called 'Pictures' in another drive or partition, it's not a Windows 'Pictures' folder;  if you have restored your backup to another drive, the 'Pictures' folder step will appear below your User name, but it won't be a Windows 'Pictures' folder. What is important is that you move the contents of the folder.

2. When you refer to "Master Folder" what is the definition? What's in it? Is it the new folder I create a level below my D drive? 

It's the top folder you have created under the upper level folder of your drive. Yes, it will be the folder you created under the D drive.

What is the best range of sub-folders within the Master?  I'm thinking a folder for all my existing images, a separate folder for my general edits, and a 3rd sub-folder for Collages and whatever else PSE 2021 rebels against having in the same folder.  Does that make sense, or am I overthinking this?

There are different ways to organize your folder structure. The general consensus is to make it simple, and in most cases to use a chronological structure. The downloader provides an option to automaticall create subfolders with a YYY MM DD template when you import from camera or card reader. That's what I am happy with.

3. If I "already" have "all my files" in my D:Users:Gerald:Photos file, is the "Photos" file what you are calling the "Master?"

For me, the master is the destination folder you have created.

4. So, could I simply drag and drop my existing Photos folder (the one currently located in D:Users:Gerald) into my newly created Photos Folder directly under the D drive (of course all from within the PSE 2021 app folder tree)?

As explained above, I expect you to move the contents (the subfolders tree) of your Photos folder into the newly created (empty) master folder. I would not move the contents directly into the D root drive.

5. What real, noticeable benefits will be realized by moving my existing Photos folder a couple of levels up from where they presently reside? What processes benefit from this move?

If you don't 'clean' the intermediate empty folder levels, you'll be annoyed by the way the folder tree is displayed in the left folder panel and by the very long folder path in various panels (especially in the information panel).

When a user with a classical setup with photo files in 'Pictures' and a catalog in the hidden location of ProgramData restores a backup in his newly created master folder on another drive with the option to keep the original structure, you get those empty folders, but that's not a big issue. The restored catalog folder is also to be found just under the restored master folder.

Where to go from here:

1. Should I leave all the existing image files where they are and just start a new folder closer to the root for new downloads and edits?

Or

2. Should I move the entire Picture folder to a place one notch down from the root? If so, what is the best way to do that without screwing things up?

To move your photo and videos from the 'Pictures' folder in your user folders to another location, you can use your folders panel in tree mode and drag and drop to another master folder in the same folder panel.

- create your new master folder where you want

- to make that folder visible in the folders panel, there must be at least one photo imported in the catalog. Place a dummy photo there and import it in your catalog.

- select the top folder of a branch you want to move, click and drag to the new folder in the panel and let go the mouse.

Note that if you already have all your files under that master folder, the process can move your whole library in a single step. That may take time (without a completion gauge... be very patient). I would always perform a full backup before.

The process is very flexible and more reliable than in Lightroom. If you have many branches to move, that may require a lot of moves, but you can choose what you move and what you want to keep in Pictures.

Another global solution is to restore your backup directly under the newly created master folder. You'll have a duplicate version of your catalog and its pictures. The main difference is that the physical folder tree will have the same folder structure, but will only contain files registered in the catalog. You'll still have empty folder steps including Pictures and your user name, but they won't be known as system folders. Then you can use the drag and drop method to bypass such an empty step, you drag the useful folder tree directly to the new master folder.

When you have moved and tested your restored catalog, you'll probably have to delete the previous catalog and its linked files to save space.

I am unable to reproduce the 'disconnected' message.

There is a way to follow better the 'collage' process and that might give us something to search.

Before clicking the 'Save Button' on the bottom, look at the 'Advanced Mode' button on the top left.

This brings you to the normal 'expert' mode, the top menu line is restored as well as the left and right panels.

You can click on the 'Layers' icon on the bottom right, and you are presented with the arrangement of layers and masks which produces the collage. Since you have the top menu, you can use it to 'Save as' and specify the .psd format instead of the .pse one, and you choose the destination of the psd.

Note that the 'Advanced mode' switches to 'Basic mode': what is displayed is not the mode you are in, it's the mode you want to get to.

Can you save normally as .psd and reopen the psd without disconnected message?