SharePoint has been around for nearly 20 years. I think it can safely be said that it has been a very successful platform and the fastest selling one in Microsoft’s history. Everything was ticking along just fine with our on-premise SharePoint environments … and then along came the cloud. Dun dun duuuuunnn!!!! And now it’s time to migrate your existing intranet to Office 365, except how?! I am not a technical blogger, so this is purely about front-end and user adoption considerations.
The bigger your company and the longer you’ve had SharePoint, the harder this is going to be. If I think about the intranet footprint at our longest standing client, a bank with 30 000 employees who are planning their move to the cloud; I shudder to think about what they’re going through right now in IT. They have terabytes of data on their nearly 20 decades old intranet, with intranets inside of intranets across hundreds of site collections and thousands of subsites, currently on SharePoint 2010. It’s not going to be an easy move. Hybrid is their answer so far. Upgrade to SharePoint 2016 on-prem and have some Office 365 footprint, migrate into the cloud completely over time.
I guess the first question then should be – should you migrate? There is nothing wrong with having your own servers, long as you maintain them. At least you have a stable environment, not one that changes on a weekly basis. Modern SharePoint lists and libraries are not for everybody, especially not people who struggle with technology. It’s too “websitey” and people are intimidated by it, apart from the weekly changes. It’s also not great when you work with tons of data, the modern experience just takes up too much real-estate at the expense of viewing critical business data. Microsoft has started to confuse what websites do, with what intranets do, but that’s a discussion for another day. Don’t do technology just for the sake of it, Office 365 is a massive platform. Have a valid business reason for migrating to the cloud and a robust plan to get there.
You may be tempted to just start your intranet again, but none of our clients will have that luxury, too much content in their intranets already. You really just need to migrate in as-is. Honestly, I think that will be the easiest thing to do. There is just way too much going on in Office 365 to plan about what you’re going to change when and how during migration. The jump to the cloud is HUGE! People are going to be overwhelmed by that much change so suddenly. They need to time to adjust to working in the cloud, understanding what new toys are available, then reviewing their existing content to decide what they will redo using the new functionality, and what will stay as is.
Critically important is to check your sharing settings on Office 365 – external sharing to anonymous users is switched on by default! You must change this!!! Your extranet must be carefully planned first.
Next, look at your list thresholds. With on-premise, we upped the limit to 100000 or more. In the cloud, that limit is 5000. Waiting (im)patiently for Microsoft to sort that out, which they say they are… It means that every list that has more than 5000 items in it, will give an error when migrated and you’re going to have to jump through endless hoops to fix it. You need to change the views before migration so that no view displays more than 5000 items. You can use the ID field for that. Do a filter to show items from 1 to 4999, then 5000 to 9999, etc etc. Or do it by year if that’s available in your data.
Decide what lists and libraries will stay in classic SharePoint and which ones can be safely switched to modern. This is based on the basic PC literacy level of your employees. And don’t over-estimate their experience, they have not been trained on best practices or tips and tricks in anything.

There will be a lot more to write on this subject, but I’m out of time for today.