I can't make the connecting symbols break so I'm assuming you mean the gaps at the corners? Those gaps are intentional and are meant to be covered by the tower symbols. The best way to draw them is by going in straight lines between the towers in a single click.

Also make sure that your default symbol scale is set to 1 in this imperial map, and that you haven't accidentaly adjusted the scale you are pasting them at by right clicking to check the current symbol scale setting.

EDIT: I also notice that the sheet effects on the SYMBOLS 3 (towers) sheet are a little off. If you make the shadow as long as the one on the SYMBOLS 2 (walls) sheet those gaps in the shadow will disappear.

Or alternatively, if you don't like the shadow overlap, you can copy the towers to the SYMBOLS 2 (walls) sheet so they cast the same contiguous shadow as the wall. in the shot below the towers are on thier correct sheet with a glow around them to raise them from the wall a little, but they are duplicated on the SYMBOLS 2 (walls) sheet for the shadow.

Oddly enough I never thought of doing it that way at all. I just redownloaded all the installers and reinstalled everything fresh and new on my new machine last December. Although it takes a bit of time it means that if anything has been updated in any of those installers I get the updated versions. The drawback is if you have made your own symbols, fills and styles. I had to transfer those across as folders and files and put them in the right place.

When you are using the new map wizard the default settings should provide you with a background you can pick. There is also a checkbox in that dialog that allows you to switch the background off entirely. It could be that you accidentally unchecked it, which would result in a missing background.

Try to concentrate on sheets rather than layers, which are of secondary importance only. If you do play with the layers (bulk hiding/freezing and unhiding/unfreezing things make sure you don't ever hide MERGE (which does some really important things behind the scenes), and try to keep MAP BORDER and SCREEN (once you have created one) frozen once you are done with creating or adjusting them. Things like that have a tendency to get deleted by mistake if they aren't frozen. Some people also freeze the BACKGROUND layer to make sure that doesn't get accidentally selected and deleted either.

Sorry - I had to go to bed shortly after I made that request, so I wasn't any help at all.

When I opened the map this morning there were only lines on the background and no background fill polygon, but there were a few other things not on the right layer. Use List from the Info menu on everything visible when the map opens and you get this:

Either the background polygon wasn't there to start with or was accidentally deleted. We may never know.

Only the map border itself should be on the MAP BORDER layer, though it can be on any sheet. Whatever is on the MAP BORDER layer defines the edge of the map within CC3 and controls how it is exported if the "Restrict image to map border" option is checked in the export options dialog when you export your finished map.

I see you have replaced the frame and drawn a screen on the FCW you shared. This can be done more efficiently after you have set up your custom frame by using the screen commands explained in this blog by Remy Monsen.

https://rpgmaps.profantasy.com/leveraging-the-new-features-of-cc3-update-26/#more-6495

Since things are a little muddled on this map, and since I don't think you started the actual drawing part of it yet, I recommend starting a fresh new map and using the sheets (not the layers) to hide everything but the map border so you can modify that first, then showing all the sheets again and using the relevant collar commands from that blog to generate your screen.

Shout again if you have any more problems.

It's in the blog, Quenten.