Just to further clarify.
Can I still file a schedule C if there is no income.
If your business was not "open for business" on or before Dec 31 of the tax year, then you do not file SCH C and have nothing to report. In such a case, if your business was actually open in 2021, then those expenses incurred in 2020 would be start-up expenses that would be reported as such on your 2021 tax return. For start up expenses, it does not matter in which tax year they were incurred either.
