Make sure your custom sheet formats location are set under Tools > Options > System Options > File Locations.
I'm having a simular problem. When i click "add sheet" it opens a default not my template which works only when i open a new drawing?
I saved a drwdot, renamed it, edited the sheet format and saved it in the templates folder (C:\ProgramData\SolidWorks\SolidWorks 2014\templates) then followed above "Tools > Options > System Options > File Locations"
There is no "custom sheet formats" so I added the link to these document templates, custom property files, and title block table template.
None of which works.
Also i noticed that some templates are in c:\programdata and some in c:\program files shouldn't they all be in the same place?
just recently wiped my computer and started all over with my file templates. I'm just a dumb welder but with my custom drawing template open I went to document properties/ drawing sheets / and set the path there.
Here is another discussion with several posts explaining sheet formats and drawing templates: https://forum.solidworks.com/thread/57204. Reviewing it should help clear up your first couple of questions.
I'm not sure what you mean in your third question. You said "There is no "custom sheet formats" so I added the link to these document templates, custom property files, and title block table template. None of which works." Right above that you said you edited a sheet format, so doesn't that create a "custom sheet format"? As far as adding the link to the templates, I assume you mean that you've gone to Tools > Options > System Options > File Locations and set the location where each type of template in the drop-down to where you have them saved. If you've done that, I don't see any reason why they aren't showing up.
For your last question, different file types in the drop-down described above don't need to be in the same folder, as long as you're accurately pointing to each type. You need to click on each type in the drop-down and make sure the right location is listed in the box below the drop-down.
Thank you for the help and link which solved the issue.
1. edit sheet
2. save sheet as template
*3. (from link above) click file, save sheet format
4. Tools > Options > System Options > File Locations. add folder location for templates
5. may or may not be necessary, (from link above) "There is a setting under Options > System Options > Drawings for "Show sheet format dialog on add new sheet"
#5 is annoying and not necessary so i unchecked the box again.