Successful tenant to tenant migration of Microsoft 365 to the Erste Group environment

After the successful user migration from google suite to microsoft 365, an excellent team of consultants followed up the project with a tenant to tenant migration to the international erste group environment.

Realization 2022

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Customer Profile

Česká spořitelna is the largest bank in the Czech Republic in terms of the number of clients. It provides services to individuals, small and medium-sized companies as well as towns and municipalities. It is also part of the strong Erste Group, which operates in Central and Eastern Europe through a network of more than 2,600 branches in seven countries. Česká spořitelna also provides banking services to the ARICOMA Group, which includes AUTOCONT.

The Tenant to Tenant migration in Microsoft 365 environment was a top priority bank-wide project for Česká spořitelna a.s., which was completed on schedule and in full. Minimising the impact on users was a major challenge of the project. After our experience with the migration from Google Suite, we were well aware that the project's impact would more or less limit all the bank's employees. I believe that we did our best in cooperation with our suppliers and managed the project with honour. We see AUTOCONT and its partners Orbit, Software ONE, GreyCorbel as suppliers who are capable of implementing very demanding projects and can be relied upon.

Miroslav Lhotský

COE Integration & Internal services lead

Baseline and project objectives

The ERSTE Group continues the IT integration of banking institutions according to its long-term plan. One of the goals is to integrate the Microsoft 365 environment so that the efficiency of collaboration of Microsoft 365 users across the Group is as high as possible.


  • Secure and efficient communication throughout the Erste Group
  • Sharing data in a secure and efficient way 
  • Easy integration into group teamwork
  • Easy access to all information
  • Unified identity 
  • Unified management and support of the M365 environment 
  • Unified environment for running banking applications across the group 
  • Potential for further expansion and integration


We designed and implemented a complex migration project for the bank. The decisive factor in the success of the project was an experienced team, whose key consultants had invaluable experience from previous migrations from Google Suite to Microsoft. Experts in technology, security, compliance, governance and adoption and communications were involved. The solution covered the complete Microsoft 365 application portfolio including Dynamics 365. Migration from Česká spořitelna tenant to Erste Group tenant was implemented. Česká spořitelna thus joined the group environment alongside Erste Bank und Sparkasse (Austria), Slovenská sporiteľna (Slovakia), Erste Bank Hungary (Hungary), Banca Comerciala Romana (Romania) and Erste Bank a.d. Novi Sad (Serbia).

The project in a nutshell
The project started in June 2022 with the assessment phase and continued with the migration phase until December 2022. A key milestone was the physical migration during a long weekend in November, using a public holiday to minimise the impact on users. After this milestone, users started working fully in the Erste Group environment. Subsequently, user support and babysitting took place for the next three months. An international team worked on the project, involving more than 50 experts from both the supplier and Česká spořitelna, including administrators from Erste Group. The main language of communication in the international environment was therefore English.  For the technical part of the migration, AUTOCONT together with specialists from partners ORBIT, GreyCorbel, CES EA and SoftwareONE delivered a number of specific tools and procedures that enabled a controlled and fast migration. Throughout the project, our adoption team ensured user awareness and readiness for the change and promoted user satisfaction with the process. Users were informed about the project and its benefits, and the upcoming steps by individual Microsoft 365 applications. Specific communication was made to each group or user including complete information about the preparation steps, set up processes, training and support. Staff ambassadors were also involved in informing and supporting their colleagues.

Gradual migration or big bang?
For the implementation of the project, the approach of gradual migration in waves or migration in one wave "big bang" was considered. Given the need to minimize the impact on business, the single wave option was chosen. This process was validated by a pilot migration, which for such complex projects is usually split into two phases. In the first phase, the IT migration was carried out, followed by the migration of all users, already verified by practice. This approach was appreciated by the bank, the migration went according to plan, without any impact on the business and no major incident occurred during the migration. Partial problems were subsequently resolved promptly. The complexity of the entire migration project is underlined by the scope of the migration, which included Microsoft 365 services including data and files, Dynamics 365 and approximately 100 other applications, while in this context, the project involved an additional 100 application administrators from Česká spořitelna and its external partners. At the same time, all Microsoft 365 services and all data were secured according to the Erste Group security standard. Orbit's proven Task Control project management application was used to manage the migration process and the entire project, including ensuring that all staff involved were fully informed. After the migration, there was significantly increased support as well as training and informing users about the new possibilities that integration into the Erste Group environment brought. Best practice when migrating such a large number of users is to maximise support capacity. A large part of the queries and requests were captured by the vendor's adoption team, through a designated team in Teams. This relieved the burden on Česká Spořitelna's Helpdesk. Together, the challenging first days after the migration were managed. After handling the first onslaught of user requests, the situation stabilized and all requests were gradually handled.

Overall impression and other challenges
Once integrated into the Erste Group environment, users positively evaluated the ease of joining and scheduling meetings with the ability to see colleagues' calendars, the ease of sharing files across the group, and the completely natural collaboration in teams. In addition to these benefits, the project also became an opportunity to focus even more on the additional capabilities of Microsoft 365, to deepen users' knowledge and strengthen their overall competence in using Microsoft cloud services in the future. The project went according to plan, the business was not disrupted by the project, deadlines and key milestones were met and the project was judged a success from the customer's perspective.

Used technologies

  • Microsoft 365


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