Formula omits adjacent cell? Help!

I have been working in this excel sheet for the past year and all of a sudden out of nowhere the entire sheet goes haywire on me. The formulas are correct but it's like they all just stopped functioning for some reason. Looking below, column B is the input data. C is suppose to update cumulatively (i.e. 1, 2, 3, 4, 5). The formula is correct in the C column but it's still displaying 0.0 all the way down. The only clue is that the error comes up on every cell in column C and it says Formula Omits Adjacent Cell. This has never happened before and this is affecting the entire sheet now, even all the successful pages prior to this. There's about 35 tabs in this document. Can anyone please help?

A B C
1 2018/03/01 1.0 0.0
2 2018/03/02 1.0 0.0
3 2018/03/03 1.0 0.0
4 2018/03/04 1.0 0.0
5 2018/03/05 1.0 0.0
6 2018/03/06 1.0 0.0

Without seeing a copy of the file (as previously suggested), it's just guessing.

Check that calculation is set to Automatic on the Formulas Tab
Check for any circular reference errors (error checking also on the formulas tab)

I wouldn't be concerned about the 'omits adjacent cell' error. You can hide that in File - Options - Formulas - error checking rules.