Andy Tidd has IT responsibilities most technology professionals will never have to tackle. As global CIO and senior vice president of ABB, a power and automation technology company based in Switzerland, Tidd regularly makes decisions that affect more than 140,000 employees in nearly 100 countries.\u00a0\nA little more than a year ago, Tidd completed one of the largest technology deployments of his career by moving 125,000 ABB employees from IBM Notes to Microsoft's Office 365. The IT veteran had handled massive IT projects before, but the move to Office 365 touched the largest number of users in the shortest period of time during his career, Tidd says.\nThe switch is also a significant win for Microsoft, according to Carlo Spetter, the company's global business manager, who calls it "one of the largest deployments of Office 365 to date." Microsoft won't say how many of Office 365 business customers have more 100,000 employees, but based on Spetter's comment, there likely aren't many.\n[Related Feature: How Motorola Solutions (and its 22,000 workers) ditched Microsoft for Google]\nTidd began this journey more than two years ago, when the latest productivity, communication and collaboration tools made it abundantly clear that ABB needed a change, he says. Prior to the move, the company had been using a locally managed version of IBM Notes, along with a collection of voice, video and screen-sharing tools from Cisco and other vendors.\nAfter extensive evaluation, Microsoft gets the nod\nABB, one of the world's largest engineering companies, was anxious to move its staff beyond what was then a simple mobile experience for email. Under Tidd's direction, ABB decided it wanted not only a simpler platform, but also one that kept employees engaged and connected.\nABB researched a variety of on-premises and cloud-based solutions before performing its formal evaluation, according to Tidd. "When we looked at what was available and how the services were developing, the feeling was that we didn't have to hold onto this in-house."\n ABB \nAndy Tidd, ABB CIO\n\nMicrosoft received high marks in all areas ABB tested, but it was never a foregone conclusion that Microsoft would get ABB's business. "When we added everything together it was a very close decision," says Tidd. "We had an existing relationship with Microsoft, and we just felt it was a better fit in terms of both functionality and our ability to work with [Microsoft] on an enterprise level."\nABB's (mostly) smooth transition from IBM Notes to Microsoft Office 365\nABB completed the project about six months after its research project began, due in large part to an aggressive plan that moved as many as 5,000 employees to Office 365 per week, according to Tidd. The majority of ABB employees have now used Office 365 for a little more than a year, but until now Microsoft and ABB didn't discuss the project at all after it was first announced in April 2013. (Microsoft and ABB recently reached out to see CIO.com with this exclusive update on the project.)\n[Related Opinion:\u00a0Why Google's enterprise pitch is a confusing mess]\n"I was very keen to move as many people out of more commoditized services into areas where they could support the business, and this seemed a good opportunity to do that," Tidd says. The migration went smoother than the CIO expected, the result of vigorous preparation by ABB and Microsoft, according to Tidd.\nHowever, the company hit a few snags while moving data from its existing systems to the equivalents in Office 365. That data transfer to Office 365 required some heavy lifting, but Tidd says the challenge didn't impede the ultimate goal: to ensure employees were happy with the new collaboration and communication tools what would ultimately make them more effective and productive.\n"In the early days there were a couple of things where people were getting used to just a different user interface and a different set of functionality, but the benefits of moving far outweighed any of the issues that we hit early on," says Tidd.\n"CIOs should know that Office 365 deployments and transitions of this size are not just one-to-one technology replacements, but a fundamental cultural transformation of their organization," Spetter says.\nAs such, ABB's detailed preparation before the migration was critical, according to Tidd. That preparation entailed "significant training" for employees, including online sessions from Microsoft, as well as local workshops designed to familiarize employees with Office 365 features. ABB also maintained an open line of communication with Microsoft to answer specific questions from employees.\nLooking back on the project, Tidd encourages his colleagues in IT not to fear the unknown or assume that all technology migrations will cause heart palpitations. "Even though we went into this to open up the collaboration and to provide a better user experience, I've just been pleasantly surprised at how good it's been for our users," he says.\nOffice 365 unlocks power in employee connections\nThe company's employees can now make more meaningful connections with colleagues and coworkers, which is "extremely important," Tidd says. Yammer, which lets workers find colleagues and see if they're available, and then start conversations, is particularly popular among ABB's employees, according to Tidd.\nThe ABB engineering teams today collaborate more and frequently seek advice from colleagues located in other countries, he says. Employees can now pull together virtual teams and work on particular projects or R&D tasks. Engineers and other technical talent frequently check in with these virtual teams, as well, according to Tidd.\n"That kind of extended workflow \u2014 we simply couldn't work in that way before, so it's been a great step forward," he says. "Before, it was all a case of who you knew and who you're able to connect with, and all of a sudden the power of the connection has gone to another level."