How a US regional bank moved 1,000 users to OneDrive without breaking its legacy financial software
CASE STUDY · FINANCE & INSURANCE
Two things are true of almost every US regional bank at once. First, the software estate depends on financial applications that pre-date cloud storage and expect real Windows drive letters. Second, regulators expect record retention, legal holds and eDiscovery to work uniformly across every piece of business content, wherever it lives. Files on personal Q: drives fail the second requirement. Moving those files to OneDrive with the standard sync client breaks the first. Cloud Drive Mapper is what let a 50-year-old US regional bank resolve the collision: 1,000 users migrated into individual OneDrives, every legacy application still working, and record retention plus legal search finally enforceable across the estate.
The whole goal was to implement record retention within OneDrive and within the SharePoint environment. Cloud Drive Mapper allowed us to have all that by moving to OneDrive, and then supporting a OneDrive connection as if it were just a normal, everyday network connection.
Software Support Engineer, US regional bank
The challenge: two problems that block each other
The technical problem was the one every financial-services IT team knows. Financial software is a very small vendor market. A lot of the applications a regional bank depends on were architected in the early 2000s and are still supported by small teams (sometimes a family, sometimes a single engineer) who never rewrote them for the cloud. They expect a Windows file system with real drive letters and real file paths. Point them at a folder managed by the OneDrive sync client and they break, or misbehave, or produce corrupted output.
The governance problem was harder. Every employee had a personal Q: drive that had, in practice, become a permanent archive of everything they had ever worked on. Record retention existed as a written policy, but was not enforced by anything the users touched. Nobody threw anything away; nobody could easily search across everything; and nobody could confidently execute a legal hold or discovery request against local files scattered across 1,000 employees' Q: drives. For a bank operating under US financial regulation, that gap was not sustainable.
On top of both, the bank runs a Citrix environment where desktops are master-imaged and reset every day. Nothing can be stored locally, because nothing local survives past close-of-business. Sync clients that build up profile state or hold persistent local caches are exactly the wrong shape for this. The default Microsoft answer to "move your files to OneDrive" was not architecturally available.
The solution: OneDrive that looks like a network drive, everywhere
The bank's plan was to migrate every user's Q: drive into their individual OneDrive account, so that SharePoint and OneDrive's native retention and eDiscovery mechanisms could finally have an estate to enforce over. Cloud Drive Mapper was what made that possible without touching the desktop experience or breaking a single legacy application.
CDM presents each user's OneDrive as a familiar mapped network drive with real file paths. Applications that expect a Q: or O: drive see one. Users open and save files exactly as they always had. The invisibility of the change is the whole point:
It's so seamless and so there but not there that people don't even know it's Cloud Drive Mapper. They just refer to it as their OneDrive.
Software Support Engineer, US regional bank
The implementation extended across every part of the Citrix estate. CDM was deployed on the master-imaged Citrix desktops themselves, and on the separate published-application servers, so that files saved from a published application (a legacy financial tool running on its own Citrix server, from the user's perspective a shortcut on their desktop) land in the correct user's OneDrive rather than a doomed local location. CDM's small cache footprint and its handling of non-persistent sessions make this workable inside a Citrix model that eats sync clients for breakfast.
Before rollout, the project sat inside a three-month management and compliance review cycle. For a regulated bank, this is the vendor-review gauntlet that most third-party tools do not survive: information security, legal, data protection and executive sign-off, in sequence. CDM cleared it. The actual production rollout, once approvals were in and the Q: to OneDrive migration scripts had done their work, was quick.
Results: retention enforced, and an unexpected discovery win
The primary outcome landed as planned. Every user's Q: drive is now an individual OneDrive. Microsoft 365's built-in retention labels, retention policies and eDiscovery apply to the whole estate. The unmanaged personal-archive problem is closed. Record retention has moved from a policy on paper to a control the platform enforces.
The second outcome was not on the project plan. Once the content was in OneDrive and SharePoint, legal discovery became something the bank could actually do. On the previous model, a legal hold or search request meant chasing files across 1,000 network drives and staff laptops (practically impossible, and impossible to defend under audit). Now it is an operation the compliance team runs from a browser.
When we have to do a legal search, we can do a legal search in OneDrive and SharePoint. We can't do it on a network drive or on all the laptops in our company. So if it's all in the cloud, we can do legal searches easily.
Software Support Engineer, US regional bank
Ongoing: support that keeps up with Microsoft
A regulated bank commits to a piece of vendor infrastructure for years, not months. What survives that period is not just the initial fit; it is the vendor's responsiveness when the upstream platform changes underneath. Microsoft ships changes to Office, OneDrive and Graph on a regular cadence, some of which unavoidably ripple down into every third-party tool sitting on top. What matters is how quickly the third-party ships a fix when they do. CDM's answer, over the years the bank has been running it, has been "quickly, and often before we've finished asking":
Microsoft changes something and it breaks everything completely, and then I reach out to Tom in the middle of the US afternoon, and somehow Tom from support responds within 5–10 minutes. Is he AI? He's just there and he's on the spot.
Software Support Engineer, US regional bank
About the customer
The customer is a US regional bank with a 50-year history, approximately 1,000 employees, and a footprint across mortgage lending, commercial lending and consumer banking. The bank has, on request, chosen not to be named publicly in this case study.
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