Here's the error log file that was generated when I tried to open in Excel:
XML ERROR in Worksheet Setting
REASON: Bad Value
FILE: C:\Games\Steam\steamapps\common\Xenonauts\assets\manufactures.xml
GROUP: DataValidation
TAG: Range
VALUE: R43C2,R16C2:R28C2,R30C2:R40C2,R45C2:R60C2,R1C2:R14C2,R62C2:R65C2,R97C2:R1048576C2
Just revalidated my Steam files, and still doesn't open with Excel.
Also just tried making the suggested change to ss:ExpandedRowCount and that didn't help. Also tried the same with ss:ExpandedColumnCount and that didn't help either. Tried expanding both row and column and still no love.