BlockFi lending 1099-misc

If, when you say "Schedule C box", you are referring to the "name of the Schedule C - you can put your name there, or any other name you want to call this Schedule C.  If you only want to report this interest earned and are not self-employed, then it sounds like you might have taken a wrong turn accidentally and reported it under "Business Income" instead of "Other Income". Truly, for a 1099-MISC - you have two choices - Business or other. Interest Income is reported on a 1099-INT, 1099-OID, 1099-DIV, or a  1099-B - all depending on the type of interest income. It sounds to me like they did issue you a 1099-MISC based on the following Nov 20th publication:

Cryptocurrency exchange

Coinbase has decided to discontinue sending customers 1099-Ks, the U.S. tax form that led the U.S. Internal Revenue Service (IRS) to mistakenly think traders had underreported their gains. The exchange will instead use the 1099-MISC form, at least for customers who earn interest on lending and similar products.

Therefore, follow these steps to "get it out" of the Schedule C prompt and properly put it into "Other Income:

When you are on the main page of your return - click on the tab at the top that says "Business" - "Business Income and Expenses" when you're under the Income Section. From there, delete out this 1099-MISCcompletely by clicking on the trash can at the end of the questionnaire where it gives you the option to enter another 1099 or proceed further. Get that out of this section as for your purposes, it does not belong there. 

After you have cleared that out of the Business section, click on the tab "Personal" at the top of your screen page. Select "I'll choose what I work on" and proceed. Scroll to the almost bottom where you will see the section "Other Income" and click on "Visit All". Click on "Yes", then select "None of the Above" then click on "Continue". 

If you did get a 1099-NEC, select "Yes", if a 1099-MISC, then select "No" (my guess based on your statement is that this is what you want to do) and on the next screen it will ask you about a 1099-MISC. Enter all information from the form into the appropriate boxes and finish out that section and you should be all set.