Top 10 Office 365 Migration Mistakes To Avoid [2019]

A concerned man looking at his laptop screen

Office 365 migration mistakes are common due to the complex nature of migrating to Office 365.

We have put together a list of common problem areas and hope our top 10 list will help you avoid common office 365 migration pitfalls.

Avoid these 10 Most Common Office 365 Migration Mistakes:

Mistake #1: “Who is in charge?” – Choose your project manager wisely

To some, this may seem an obvious first step but it’s surprising how many migration projects don’t have an assigned individual to run the project and take responsibility, especially for the smaller migrations.

We regularly see migration projects handled by in-house or outsourced IT departments but in many cases this is not always the best move. Unless they have an individual who has a good understanding of your organisation as a whole then you run the risk of missing critical areas of your plan. Assign someone who has a good general overview of your organisation and strategic goals, which in many cases is not a member of your IT department.

By all means assign the technical parts to your IT team but carrying out a migration has an impact well beyond this area of your organisation. It’s great if yours IT department completed a prompt and successful migration from a technical aspect. But if it leaves your sales department with an interrupted sales campaign and a reduction in your reported sales figures for the last quarter then the successful migration won’t look so good.  

Consider outsourcing this role or the whole project to a trusted migration expert, as most organisation will not have the in-house skills established by completing many migrations.

Mistake #2: “What have we got?” – Audit your current systems

Most organisations except possibly recent startups will have a great deal of information to migrate over to Office 365.

But the bigger question is:  Do you need it all? Can some be archived?

You may also find data you didn’t know you had or more data than you were expecting to migrate which may push up your running costs on Office 365. Know what you have before you migrate. This will also give you a good idea of how long your migration will take.

Mistake #3:I wasn’t told” – Involve all departments/areas of your business

With a good project manager assigned, they will be off talking to all departments and establishing contacts throughout the organisation. But just in case you don’t have a good one we felt this should be one of our ten points.

You need to include all affected departments within your organisation and involve them within your plan. Everyone needs to know, what information will be moved, how they will access it, how long they will be down and will they be familiar with the new system.

Mistake #4: “Who is doing what?” – Plan your migration well

Migration to Office 365 will take a while to complete, the larger the organisation the longer it will take. Also, unforeseeable issues may arise and usually with IT, things take longer than expected.

Allow gaps in your project were possible to allow for overruns so a delay doesn’t impact following sections of your project. This should reduce delivery pressure.

If you’re rushing to catch up with your plan, then it far more likely something will go wrong. Document every stage of your project in detail, who does what and by when and what are the dependencies to be able to continue with the next part?

You may also like to read this post on how to carry out large scale email migration to office 365

Mistake #5: “How do I log in and use Office 365?” – Training

Don’t’ assume that everyone knows how to use office 365 or can work it out if provided with a login. It is highly likely you will need to train some if not most of your users on how to use Office 365.

First, they will need to know how to log in, how to print and how to access their emails. They will need access from all the devices they had access from before, will it look different from what they were used to? Have you changed where they will find their data?

Mistake #6: “I only needed my 2019 files to start with” – Prioritise

Every area of your organisation needs their information but they don’t necessarily need it all of the time. They may need email but not historical email straight away. They may need files in certain folders on your file structure but they may not need all their folder structure straight away.

If you’re able to prioritise the migration of your data you may be able to reduce downtime for your users significantly, this will reduce the pressure of migrating information and you will be up and running with critical information more quickly.  

The accounts folders from 2016 is important information but you may not need it straight away so why migrate it first when 2019 is needed immediately.

Mistake #7: “I can’t find all my emails” – Prepare and test your Office 365 destination

If it comes to the point where you start migrating data to office 365 and you find no licenses have been setup for users or users are unable to access folder areas then this could seriously delay you project migration.

It’s well worth carrying out a test migration for each aspect of your systems well before your migration. This will allow you to address any issues you may come across when migrating your data for real, but without the pressure of users being impacted or even offline.

Migration Monster allows you to complete mailbox test migrations before you migrate for real. Click To Tweet

Mistake #8:“How did he see my files?”Maintain Security and compliance

When moving data between locations or uploading to office 365 you need to maintain your data security through the process. We recently published a post on Office 365 Security Considerations that you make like to read along this.

Who will have access to it during transition and also at its destination? This combined with retention requirements must all be managed throughout your migration.  Plan to retain archives in accordance with regulatory laws, maintain appropriate information security practices and mitigate the risks of critical information.

Mistake #9: “it’s so slow on the new system” – Network and Bandwidth

If most of your IT systems where in-house or you had a hybrid system, then use of your internal IT network will change significantly. Make sure there is sufficient bandwidth in the places you need it.

You may need to upgrade your internet connection if in the past it was just used for just general web browsing and the sending and receiving of emails. Insufficient bandwidth or a slow network will have a big impact on your user’s experience when accessing the new Office 365 system.

Also, consider resilience if your internet connectivity is prone to failure or you can’t afford for it to go down.

Mistake #10: “I can’t get in to the office” – What are you leaving behind?

While concentrating mainly on your migration to Office 365 and the decommissioning of all internal IT systems it very easy to forget about items that may need to stay behind. If you hosted centrally on your old server an Antivirus solution or your building access system, then where will these be hosted now.

Office 365 allows you to work from anywhere, you may have to work somewhere else if you can’t get in to your office building after the migration has completed due to the door entry system not responding!

Here’s the infographic below, created out of this blog post.

List of Office 365 Migration Mistakes to Avoid
Top 10 Office 365 Migration Mistakes To Avoid

Also read: How to tackle Office 365 Migration Errors & Troubleshooting?


Although we are seeing a huge take up of office 365 its not always the best solution for every customer. For large organisations the reduction of control and security may not meet compliance requirements and an in-house/self managed email solution may be better.

Office 365 vs Hosted Exchange : Pick the right one for the business
Office 365 vs Hosted Exchange : Pick the right one for the business



While moving to Office 365 has a magnitude of benefits for most organisations you need to get there in one piece. From all the above listed areas of risk one word says it all “PLAN” or risk the consequences of office 365 migration pitfalls.

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