This one's simple.

Fact 1: Every startup likely needs to hire executives externally to run big parts of the business. It's inevitable with growth that there will be a need for specific skillset or seniority that cannot be conjured up internally.

Fact 2: Executives come in wanting to contribute in a big way in bridging gaps in the existing business and fixing issues. 

The challenge is that often, Fact 2 is more intense that intended: Senior Hires want to feel like they fixed everything. This is common. At least 3 founders at startups I've worked with or advised in some capacity have said, "External execs just don't work for us because the team doesn't align".

Here's what I think is (at least) partial panacea:

• Set Expectations with the team that their incoming boss might make significant changes from their Business-as-Usual
• Set Expectations with the incoming exec that he/she'd need to work with the team to make the changes over a 3-6 month period vs. immediately coming in with a strong "let's fix this broken ship" attitude.
• Remove fear of failure. Both the team and exec need to be able to take risks and change operating mechanisms.
• The Trusted Lieutenant. Entrust the team to the executive, and entrust the executive's 'organizational coaching' to a trusted, strong, employee who embraces change, and will work with the team + the incoming exec to align everyone and fill in the (information/history) blanks where needed.

My 2c? The trusted lieutenant is usually the make-or-break factor here.