Many accounting firms are leaving Thomson Reuters Virtual Office CS for alternatives in 2026 because the platform is changing underneath them. Thomson Reuters is ending its managed Microsoft 365 email inside Virtual Office CS, pushing firms to run their own Microsoft tenant. Combined with busy-season performance strain and rising costs, firms are moving to fully managed private cloud hosting instead.
Quick summary
- Thomson Reuters ended support for Hosted Exchange email in Virtual Office CS and SaaS on August 31, 2026. Mailboxes that weren’t migrated by that date were scheduled for deletion.
- Between May and July 2026, Microsoft 365 Office apps rolled out across Virtual Office CS/SaaS environments. Firms now have to bring and administer their own Microsoft 365 license.
- That moves email administration, spam filtering, retention and DNS onto the firm — a new IT burden many practices didn’t sign up for.
- You have four realistic options: stay and run Microsoft 365 yourself, bring everything back to your own server, switch tax platforms, or move to a managed private cloud. Each is compared below.
- Whichever you choose, plan the move before January. Migrating during busy season is the one timing mistake that is hard to recover from.
What to switch to: your four options
If you’re leaving Virtual Office CS, or deciding whether to stay, these are the realistic paths. The right one depends on your team size, how much IT you want to own, and whether you plan to keep UltraTax CS and the rest of the CS Professional Suite.
| Option | Keep your CS licenses? | Who manages Microsoft 365? | Effort to switch | Best for |
|---|---|---|---|---|
| Stay on Virtual Office CS | Yes | Your firm | Low | Firms happy with performance that can run their own Microsoft 365 tenant |
| Move to your own server | Yes | Your firm | High — hardware, security, backups and updates are all yours | Firms with in-house IT staff |
| Switch to a different tax platform | No — new software | Depends on the platform | Highest — data conversion and staff retraining | Firms already planning to replace UltraTax CS |
| Move to a managed private cloud | Yes | Your hosting provider | Medium — migration handled for you | Firms that want one environment and no added IT burden |
Staying is a reasonable choice if your team is small, performance has been fine, and someone at the firm can own the Microsoft 365 tenant, mailboxes and DNS.
Moving to a managed private cloud makes sense when you’d rather not take on that Microsoft work, when busy-season slowdowns have been a problem, or when you want UltraTax CS, Practice CS, QuickBooks and your add-ins in one environment. You keep your existing Thomson Reuters licenses; the host runs the applications you already own.
For a line-by-line cost comparison for 3, 10 and 25-user firms, see Virtual Office CS Pricing vs OneUp.
What changed with Virtual Office CS in 2026
Virtual Office CS hasn’t disappeared. What changed is the service around it. Thomson Reuters stopped creating new email domains in Virtual Office CS and SaaS environments, and support for Thomson Reuters–managed Hosted Exchange email ended on August 31, 2026. Mailboxes that weren’t migrated by that date were scheduled to be securely deleted.
Between May and July 2026, Microsoft 365 Office applications were rolled out across Virtual Office CS and SaaS firm environments in phases. Your firm now needs its own Microsoft 365 tenant and individual Microsoft 365 accounts to use Outlook, Excel, Word and the other Office apps inside the environment.
In plain terms: a part of your environment that Thomson Reuters used to manage for you is becoming your responsibility. Your firm now owns the Microsoft 365 tenant, mailbox administration, spam filtering, retention policies, and the DNS records that keep email flowing. For a tax or accounting practice — where client financial data lives in email — that’s not just an IT chore. A mishandled migration can create exposure under frameworks like IRS Publication 4557, the FTC Safeguards Rule, and AICPA standards for protecting client data.
For many firms, this is the moment to step back and ask a bigger question: if we have to re-architect part of our environment anyway, is staying on Virtual Office CS still the right call?
Why firms were already reconsidering Virtual Office CS
The Microsoft 365 transition is accelerating a conversation that was already happening. The most common reasons firms cite for moving on:
Busy-season performance strain. Remote accounting has expanded far beyond occasional after-hours access. Tax, bookkeeping, audit, and client-accounting teams now run distributed workflows continuously — often late into the night during filing deadlines. Older shared environments built around lighter usage patterns can feel sluggish exactly when the firm needs speed most: large UltraTax CS returns, multi-user Practice CS sessions, and SQL-heavy operations.
Limited flexibility. Standardized hosted environments aren’t easy to tailor to a firm’s specific application mix, add-ons, and workflow. Firms running UltraTax CS alongside QuickBooks, document management, and third-party add-ins often want everything in one environment that’s configured around how they actually work. Especially to avoid downtime incidents with Virtual Office cs, firms are looking for better & trusted alternatives like OneUp Networks.
Cost and control. As firms grow, they want predictable infrastructure costs, clearer support ownership, and the ability to scale users and resources without re-platforming. The new requirement to stand up and manage a Microsoft 365 tenant adds cost and administrative overhead on top of the existing subscription.
Support ownership. When something breaks at 9 p.m. on April 12, firms want a support team that knows their environment — not a general queue.
You don’t have to rebuild from scratch
The word “migration” sounds heavier than it usually is. You keep your existing Thomson Reuters licenses — a hosting partner runs your firm-owned, licensed applications; it does not sell or replace your software. Your UltraTax CS, Practice CS, Accounting CS, FileCabinet CS, and other CS Professional Suite applications move into a private environment, along with QuickBooks, Microsoft, and the add-ons your team relies on.
OneUp Networks, the best alternative to Virtual Office CS, is a managed cloud hosting provider that helps accounting firms move the full CS Professional Suite — plus Microsoft and other business-critical applications — into a secure, private cloud designed around real CPA-firm workloads. (OneUp Networks is an independent cloud hosting provider and is not affiliated with, sponsored by, or endorsed by Thomson Reuters. All trademarks belong to their respective owners.)
How OneUp Networks helps firms leaving Virtual Office CS
1) A private cloud built for accounting performance–
Instead of a generic shared setup, firms get private dedicated infrastructure with local NVMe SSD storage, DDR5 RAM, 3 GHz+ processors, high IOPS, and low latency — the kind of hardware that keeps demanding tax and SQL-based applications responsive during peak filing periods.
2) One environment for everything –
UltraTax CS and the rest of the CS Professional Suite can run alongside QuickBooks, Microsoft 365, and your add-ons and add-ins in a single hosted environment configured around your users and workflows — so your team isn’t bouncing between disconnected tools.
3) Microsoft handled for you –
Because the Hosted Exchange change makes Microsoft your firm’s responsibility, having a managed partner set up and run Microsoft within your environment removes the administrative burden the August 2026 sunset creates.
4) Backups and disaster recovery built in –
Data is protected with three backup copies across one onsite and two offsite locations, a 120-day rolling retention window aligned with Veeam recommendations, and a built-in disaster recovery plan — with a recovery point objective of roughly 2–4 hours and a recovery time objective of roughly 3–4 hours. At any given time there are multiple running copies (primary site, DR site, and backup copies), which helps protect against outages, data loss, and ransomware.
4) Security-focused infrastructure –
Private dedicated servers, physical and software firewalls, enterprise-grade endpoint detection and response, multi-factor authentication, encryption in transit, IDS/IPS, DDoS mitigation, role-based access controls, and tenant isolation — hosted in AICPA-approved data center facilities and following IRS cybersecurity guidelines. The underlying data centers support leading compliance standards including SOC 2, HIPAA, PCI DSS, and ISO 27001.
5) A structured migration, not a rushed one –
Moves follow a defined path — discovery and environment review, architecture and migration planning, setup and data migration, go-live with user onboarding, and post-go-live hypercare — so the transition is predictable and can be scheduled around your busy season with minimal downtime. OneUp can also coordinate with vendor support, including Thomson Reuters and Microsoft, to resolve issues faster and reduce the load on your internal team.
Virtual Office CS vs. a Managed Private Cloud: side by side
| Factor | Virtual Office CS / SaaS (2026) | OneUp Networks – managed private cloud |
|---|---|---|
| Microsoft 365 / email | Firm must run its own Microsoft 365 tenant since Hosted Exchange ended on August 31, 2026 | Microsoft set up and managed for you inside your environment |
| Performance | Shared environment; busy-season strain commonly reported | Private dedicated servers, NVMe SSD, DDR5, 3 GHz+ CPUs, high IOPS |
| Application scope | Remote access to CS Professional Suite apps | CS Professional Suite + QuickBooks + add-ons + Microsoft in one environment |
| Backups & DR | Managed by Thomson Reuters | 3 copies (1 onsite, 2 offsite), 120-day retention, DR plan, RPO 2–4h / RTO 3–4h |
| Support | Thomson Reuters support queue | Managed support with vendor coordination (Thomson Reuters, Microsoft, Intuit, CCH) |
| Licensing | Firm owns its CS licenses | Firm keeps its own licenses; OneUp hosts your client-owned applications |
| Customization | Standardized environment | Configured around your users, applications, and workflows |
For larger CPA firms
Larger practices and multi-user firms that want hosting, migration, premium support, disaster recovery, and a scalability roadmap in a single plan may be a fit for the Total Practice Plan — OneUp Networks’ highest-tier managed hosting designed specifically for CPA and accounting firms, with a dedicated account and technical manager and 24×7 premium support.
Some other reasons (in %) why firms are looking for Thomson Reuters Virtual Office CS alternatives like OneUp Networks-
Frequently Asked Questions before Migration:
No. Virtual Office CS is still available. What ended is Thomson Reuters–managed Hosted Exchange email inside Virtual Office CS and SaaS, on August 31, 2026. Firms now bring and manage their own Microsoft 365 license, and that change has prompted many to reevaluate the whole environment.
No. You keep your own Thomson Reuters licenses. A cloud hosting partner works as Virtual Office CS alternatives and runs your firm-owned, licensed applications — it does not provide or replace the software itself.
Thomson Reuters no longer manages Hosted Exchange email, and mailboxes that weren’t migrated were scheduled for deletion. Your firm needs its own Microsoft 365 tenant. A managed hosting partner can set up and run Microsoft 365 for you, so email administration doesn’t fall on your internal team.
Yes. Migrations follow a structured, phased process designed to minimize downtime, and the timing can be planned around your filing calendar rather than during peak deadlines.
The UltraTax CS Hosting is built with enterprise-grade security controls and hosted in AICPA-approved data centers that support standards such as SOC 2, HIPAA, PCI DSS, and ISO 27001, following IRS cybersecurity guidelines. No provider should claim to be “100% secure,” but the environment is designed to protect sensitive tax and accounting data.
It depends on how much IT you want to own. If you’re comfortable running Microsoft 365 yourself, staying may be fine. If you want to keep your UltraTax CS and CS Professional Suite licenses without taking on Microsoft 365, email and server administration, a managed private cloud is the closest like-for-like replacement. It runs the same applications, plus QuickBooks and your add-ins, in one environment.
The change Thomson Reuters has announced for Virtual Office CS is the end of Hosted Exchange email, not the end of Practice CS. If you’ve heard otherwise, confirm the current status with your Thomson Reuters account representative. Either way, Practice CS can be hosted in a private cloud alongside UltraTax CS and the rest of the CS Professional Suite, so you can plan your next step without rushing.
Virtual Office CS costs $147 per portal per month before storage, support and setup fees. OneUp Networks hosting starts at $49.99 per user per month, and migration is included. See the full cost breakdown by firm size.
Plan your move before busy season
The August 31 deadline has passed, but the right time to migrate still depends on your calendar, not Thomson Reuters’. Most firms move between September and December, so the new environment is settled and the team is comfortable before the January rush. A structured migration takes weeks, not months, and it can be scheduled around your deadlines.
Keep Your Accounting Workflows More Stable During Busy Season With OneUp Networks
When Virtual Office CS environments begin slowing down during tax season, the problem usually extends beyond simple software frustration. Many accounting firms eventually experience growing workflow pressure caused by overloaded remote environments, unstable accounting responsiveness, reviewer bottlenecks, and increasing concurrency across distributed accounting teams.
Those operational slowdowns become more noticeable during filing deadlines when multiple departments remain connected simultaneously throughout the day. Reviewers reconnect repeatedly, accounting applications respond inconsistently, and teams begin creating temporary workarounds simply to maintain workflow continuity during busy season, this calls a search for Virtual Office alternatives
OneUp Networks helps accounting firms move toward more stable accounting-focused cloud environments designed around real CPA-firm workloads instead of generic shared hosting environments. With centralized infrastructure, smoother remote accounting access, improved multi-user application performance, and accounting-focused operational support, firms can maintain more predictable workflows across QuickBooks, UltraTax, Thomson Reuters, CCH, and other accounting applications during high-pressure workload periods.
- Contact Us: Talk with specialists who understand accounting workflows and hosted tax environments.
- Book a Demo: See how a stable accounting-focused cloud performs under real multi-user workloads.
- Start a Free Trial: Experience smoother remote accounting in a private cloud built for CPA firms.
- Request a Quote: Receive a tailored hosting recommendation for your firm’s workload and users.
With OneUp Networks, firms gain more than hosted infrastructure—they gain an accounting-focused environment designed to support steadier workflows, more predictable performance, and smoother operations during tax season.
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