I just spent about three hours redesigning a sheet format, including custom properties and a custom properties tab. Every time I try and save the format as, for example, 'Format1.slddrt', it throws the error 'An unknown error occurred while accessing C:\ProgramData\SolidWorks\SolidWorks2014\lang\english\sheetformat\Format1.slddrt.' I have done this before without problem while not using a custom properties tab, so I'm thinking that's the issue. Everywhere I've looked says the problem might be with date fields, but I'm only using text fields with no other requirements. I am using solidworks 2014 if that makes a difference. I can save the drawing file fine, and when I re-open it, the formatting is consistent. I just can't save the formatting on its own to create a template. Thanks for the help.