When I was an experienced hire candidate, the background checks were made through phone calls to some (not all) of the references I provided.

In terms of asking to disclose/not disclose, I think you could request for them not to reveal, but personally I would get references that I'm close enough to, to be able to reveal that its McKinsey you are joining. If they are truly close/supportive/know you well, then its also likelier their stories about you will be more positive

Hi there,

Congratulations on the McKinsey offer!

I got some requests for background checks for candidates that I hired in my company and then moved to consulting. I answered your questions below based on my experience. 

Please note there may be differences depending on the country and third-party company involved with the check.

1) How is the background check of employment conducted? through phone calls?

In one case I received an email from the third-party company doing the background check. In another case, they called first, then sent an email with the information to check.

2) if through phone calls, can I ask them not to call my current employer until after I resign? because my start date is still mid-next year and Its too early for my employer to know I'm leaving

This should be feasible, please let HR know that in advance.

3) Do they inform my previous and current employers i'm joining mck? and if so, can i ask McK not to disclose that im joining them?

One of the emails I got was not saying the company for which the person was recruited; another was mentioning it.

Best,

Francesco

Hi there,

Some background checks are via phone others through email - try not to worry about this.

You can ask them to make sure not to do this (regardless, they shouldn't be contacting your manager…only HR).

Checks with previous employers are usually done with a call.

They will not call your current employee if not after you joined the firm.

Hi there,

Typically they contact your HR via email and you can verbalize any concern you have to the TA team.

Mario

The background checks are contracted to a third party and generally are a phone call or email. If you work for a large organisation they will call the main HR to ask if you are working there - generally this won't come through to your line manager. However, if you're anxious I suggest that you speak with recruiting to ask them if the firm could exercise discretion.