Commercial product name similar to open source product name

I have a commercial software product that will be launching soon.

It has a very similar name to a piece of open source software in a non-English speaking country. The only difference is a space.

Both products have similar goals but approach them in totally different ways, but could be seen to be in the same general market.

The open source software is not that popular from what I can see, but has been updated recently.

The name is not trademarked.

Should I:

1. Change my product name (something I really don't want to do).
2. Approach the maintainers of the project and ask them if they mind me
   using a very similar product name.
3. Forget the other product exists and launch regardless.

Change the name.

1. If the names are similar and you're in similar spaces, customers looking for you are likely to find them first. That's a problem.
2. Further, you'll be competing with them head to head in Google. If they have any sort of community, twitter/blog presence, etc, they should come up ahead of you for quite a while.
3. Also, you'll have to deal with all the online baggage of that other project. If there's ever a negative review of them, it will reflect on you. If they have a security vulnerability, it will reflect on you. (That goes both ways.)
4. When you do start getting mentions, reviews, etc.. what happens when the person means you but links to them by accident? Oops.
5. If the project's users are looking for help and find you, will you be stuck responding to support email, calls, etc? Even a polite "that's not us" burns up time when you multiply it by a few hundred.
6. Finally, their less clueful users might find you and throw a fit that "project X has sold out." It's just more annoying than anything.

If you can avoid the name collision, do so.

#3.

The previous answer is very careful and safe, but excellent names are hard to come by. If the name you have in mind is a very strong one that fits well with your product, then I would launch forth with it as is.

The world is a big place and almost every decent word/letter combination has been used for something somewhere. If no one ever used a name because somebody else, somewhere at some time used it or something similar to it for something, then no other products would ever launch.

In this case, the usage is more current and topically relevant, but they sound small and, if they are likely to stay small, then I don't think you should not use the name you want because of them. There are some potential complications as has been pointed out, but the effort to find a suitable alternative that's completely clean and complication-free is not necessarily simple or quick.

The only things that would lead me to suggest otherwise are: a) if the other firm is likely to become a huge success in the near future before you have a chance to gain traction, and b) if they own the domain name(s) for the name.