Made party to individual without his firm

In case of proprietorship firm, complaint can be filed  in the name of proprietor or the firm. If the the complaint is filed in the name of proprietor it should be pleaded that the accused is prop. of the firm which issued the cheque. Refer to Milind Shripad case of 2011SC. No defence to the accused except denial .  

Advocate Mr. Thukral is right.  In a sole proprietorship company, a complaint need not necessarily be against the firm alone, it can be filed against the proprietor also because it is his firm and he cannot deny his firm's liabilities, go ahead.

File it against proprietor, agree with experts

Proprietorship firm is not a legal entity, the proprietor is the legal person behind the firm.

So there are three ways a complaint can be maintained against such accused.

1. Against X the proprietor of proprietorship firm Y.

2. Simply against X, but some reference to the firm name must be given.

3. Against the proprietorship firm Y.

4. Against both X and Y (two accused)

Sr# 3 is lawfully incorrect, but the complainant can take refuge in the fact that he was not aware about the internal management of the firm and as per CPC (in absence of any other guidelines) the accused/respondent is required to state the facts about the firm constitution on first presence. Ideally Sr#1 is the best.. Incase of Sr#4, there are few instances of various HCs wherein the proceedings against proprietorship firm is quashed and continued against the proprietor only.