How do you handle this situation when a big number of your employees resign at the same time?

Good question. First I need to find out the reason. But if I can't avoid thi mass resignation, I must have back up plan for other emplyees

Accept it as a challenge and find the reason for the same. Take it as a learning and find solution/ corrective measures to avoid re-occurrence. 

It is very unfortunate that the whole team has resigned on the same day. It seems to be matter of dissatisfaction of employees & grievances against the company. 

Take the team into confidence. Try to ascertain the roots cause of such act among employees. Make them feel important to retain them.

"PEOPLE QUIT BOSSES, NOT JOBS." ....... Find your own weaknesses and take corrective measures immediately. 

If the issue is different, e.g, BETTER JOB OFFER or HIGH EARNINGS..... I would advice to call CEO to have a joint meeting with all team members...... I am sure CEO with his experience and authorities, can easily handle the situation. 

If you will be able to retain the TOP performers, be sure that you save almost everything. 

There must be an underlying issue if most or all of the same team resign at the same time;  Try to get to the bottom of it.  Are they unhappy with something / someone within the company?  If yes, see if anything can be done to correct this (even if it does not help you keep some of these staff members, it will help fix the issues for the future).

You need to have a very honest conversation with each person to identify what is going on.

If you cannot retain any / all / some of the team, then you need to figure out a solution on how will you function going forward.

Not sure how critical this team is to the business - i.e.: client facing team or back office team.

As this will dictate how quickly you need to find other resources, you might need to opt for some temp staff to help fill the gap until you can find new perm. staff.

Good luck

Stand on the reason for the resignations and give priority to the cause of the resignations and the importance of each person in the organization and to approve the resignations of persons who have no importance and negotiate with people who have a weight and keep in the organization

With the other into account the work on the second generation processing so that there is no vacuum in the case of mass resignations

Yeah, a whole office resigning at once is rarely going to be welcome news.

Normally people should handle their own resignations individually, but having the whole office all resign within a few hours (or days) of each other is the type of thing that you can’t pretend isn’t weird.

So in this case, you should probably give the main office a heads-up about the whole situation. I’d suggest that you just have one conversation with the main office to cover the whole situation.

(I’m assuming that under normal circumstances, people in your office hand in their resignations to your manager, not to the main office. If I’m wrong about that, I’m still going to suggest that you have one big conversation with the main office about all the resignations. This is an unusual situation, and it’s reasonable to acknowledge that by handling it differently.)

Thanks for the invite,

I go for and vote up the answer provided by Mr Emad Mohammed

This is our responsibility to retain current employee because good workers are asst for any organization. Find out issues, try to solve them if impossible then do necessary as per project requirement.  

You must investigate the issue and why they are giving resign, negotiation and insure the compliance and policies to the employees and informed them about disadvantages to do. 

No matter how desirable your company is as an employer, employees resign. Employees resign for many right reasons - and occasionally, for wrong reasons, too. Employees move to be closer to family when they decide to start a family because they want to live close to a support group to help raise their children. Employee spouses or partners accept outstanding job offers or medical residencies that are out-of-state.

Employees resign because they receive job offers that will catapult their careers when similar opportunities are unavailable in your firm. Employees resign to leave  bad bosses – though shame on you, if you allow this resignation to occur.

These are all positive reasons why employees resign. They may not be as positive for the employer. Here's how to handle the details when an employee resigns.

Following your receipt of the employee's official resignation letter, work with the employee's supervisor to make certain that the employee's last two weeks remain positive and contributing. If the employee has provided the standard and expected two weeks' notice, you have ample time to wrap up the employee's job.

If the employee is viewed as a threat to the ongoing work and environment for your other employees, you can walk the employee to his car and terminate the employment relationship immediately.

This is fortunately, a rare situation, so you normally have the opportunity to wrap up the employee's job and pass the work to other employees while you begin the recruitment for the employee's replacement.

Or, you may rethink the organization of the work and the department as a whole. An employee resignation is also an opportunity.

You will also want to work on:

• planning the recruitment for the replacement employee,
• holding an exit interview with the terminating employee, and
• accomplishing each activity on the employment ending checklist.

Employment resignation can be managed so that you minimize the impact of the loss of the employee on your work flow and work environment. Handled effectively, the exiting employee leaves knowing that he or she has contributed and added value during their time in your employment.

Encourage the employee's department to hold a recognition and farewell event for the employee before his or her last day. Follow your standard procedures in your employment ending checklist for the employee's last day.

find route cause...try to retain atleast the good one...have one to one discussion...