This is a question we hear from customers and our internal team all the time: “Does Office 365 ‘work’ on Citrix? Isn’t it just the same as what we have always done?”

When I’m asked this question, the first thing I always do is clarify which part of the O365 suite they are asking about. Without going too far into Microsoft’s licensing models, O365 subscribers are typically entitled to two key capabilities (among many others): Exchange hosted as a service, and OneDrive for Business (OD4B) hosted as a service. These entitlements also include some pretty serious capacity, with 100 GB mailboxes and 1 TB+ of OD4B storage per user. 9/10 times, when someone is asking if O365 works with Citrix, they are ultimately talking about Exchange, OD4B, or both.

So, back to our initial question, the second part is a pretty straightforward answer. While users are often directly interacting with Office 2016 apps that look more or less the same to them as they always have, where their data resides, how they authenticate and how their Office products are activated change pretty significantly.

As for the first part of the question, let’s dive into that answer by component. On the Exchange side, those 100 GB mailboxes are pretty hard to pass up, meaning we see more and more customers migrating to hosted Exchange. But for all you Star Trek fans out there, that also means we just violated the prime directive of designing a Citrix environment! We just moved the data away from the workload (user session). This means we have latency between the VDA and Exchange, and that means we are now forced to use Cached Exchange Mode or another option like OWA. The UX just isn’t there in Online Mode. And that’s not just me or ‘Citrix’ saying it, that comes straight from Redmond:

We have also certainly had our share of customers decide they preferred Cached Mode even when Exchange lived right next to their Citrix workloads long before O365 was around. Once we enabled Cached Exchange Mode, we are now in the wild world of .OSTs. A little side note, I still hear folks say all the time that redirecting .OSTs isn’t supported. While MSFT used to be pretty strict here, they’ve actually relaxed their statement on this front some over the years and we’ve had customers doing this for quite some time (in some cases 10+ years back to the .PST days). This gives us a way to deal with the email cache in a persistent manner (even when we are talking a non-persistent workload), but there is one more problem. The search index the Outlook search experience depends on is currently machine based (at least until Server 2019? ;)), making it very difficult to deal with and ultimately roam on a per user basis. The result is a less than favorable user experience, at least initially, that we really didn’t have a way to deal with too well without third party solutions… until now! I’m sure you have seen recent announcements around the O365 User Layer as part of Citrix App Layering. If not, you can read about it here. The O365 User Layer gives us another way to deal with .OSTs, but still doesn’t solve that pesky index problem. But there is relief to be found. As part of UPM 7.18, Citrix released the Native Outlook Search Experience, which allows us to roam not only the .OST, but also the search index per user.

Covering all angles of this topic could probably be a multiple part blog series all by itself, so I’ll move on to OD4B. But if you are interested in hearing more about pros, cons, recommendations and gotchas, of the O365 User Layer, UPM and the ‘old school’ options, those will all be covered in the webinar (registration link below).

On the OD4B front, Prime Directive violation #2. I’m starting to feel like Kirk over here! With user data moving from traditional on-prem file storage solutions (near the VDA) to a cloud service, the challenge again is really how we handle sync of OD4B data in non-persistent and multi-user (XA) environments. Syncing potentially GBs of data into these non-persistent (and potentially multi-user) VDAs wreaks havoc on resource utilization, storage demands, network throughput requirements, etc. While MSFT introduced an on-demand sync for Win10 in the Fall Creator’s edition, this capability does not exist for other desktop OS versions, nor is it supported on Server OS. To provide a consistent experience to users across multiple access methods, this means customers are often left getting creative, perhaps a bit outside of what is supported, sacrificing UX, or looking at 3P solutions. What many customer don’t realize is that Citrix Files (the artist formerly known as ShareFile) is also a tool we also have in the arsenal to help address this very challenge. The Citrix Files client offers on-demand sync support for both Server and Desktop OS and is capable of serving as a data aggregator for OD4B data. This gives us a supportable way to make use of the OneDrive storage we have already paid for even in non-persistent environments, while still providing a favorable user experience.

To learn more about Exchange and OneDrive options and recommendations, as well as authentication and activation considerations, please join Pierre Marmignon (Principal Product Architect) and me for a free webinar on August 9th at 9AM or 2PM ET. There will also be a live Q&A at the end where you can pick our brains on anything Citrix + O365 related – after all, who doesn’t like a little free consulting and PM time!

Watch the webinar on-demand today!

Feel free to drop a line below if there are any additional Citrix + O365-related topics you’d like to see covered.

Ryan McClure
Citrix Consulting Enterprise Architect