At the end of September 2025 several administrators reported a recurring and highly disruptive pattern: Remote Desktop Session Host (RDS / Remote Desktop Server) instances would suddenly stop responding to user input while sessions remained “attached” and displayed only a black screen — and Trend Micro’s Worry‑Free Business Security (WFBS) agent was implicated. Trend Micro support told at least one affected customer that a targeted agent build — 6.7.4065 / engine 14.3.1342 — had been rolled out and “should” address the freezes, but community feedback is mixed and real-world validation remains incomplete.
This feature article explains the symptoms, traces the vendor and community responses, verifies the technical claims where possible, and offers a practical, risk‑aware remediation path for administrators running RDS in production. It synthesizes vendor documentation, the BornCity reader report, Trend Micro support guidance and independent community reports to help IT teams decide how to act now.
Background / Overview
Remote Desktop Server freezes described by multiple readers show a distinctive pattern: existing RDP sessions stay “connected” but the remote client displays a black screen and all keyboard/mouse input is ignored; new logons also hang. The only reliable recovery step reported by affected admins is a full server restart. The incidents often repeated at similar clock times across different VMs — a pattern suggestive of a scheduled agent task, update or scan.Trend Micro’s WFBS (Worry‑Free Business Security) is widely used in SMB and midmarket environments and runs a resident agent on servers. The agent performs real‑time scanning, behavior monitoring and scheduled scans/updates. On Windows Server hosts these hooks touch sensitive subsystems — the Desktop Window Manager (dwm.exe), Remote Desktop Services (termsrv.dll/termsrv.exe) and display/graphics stacks — which are plausible choke points for interference if the agent actively inspects or blocks process behavior. Official Trend Micro guidance for server deployments already documents areas where exclusions or configuration changes are recommended to avoid functional interference.
What administrators are seeing: symptoms and evidence
Characteristic symptoms
- Existing RDP sessions remain connected (session state preserved) but show a black screen; input stopped working.
- New RDP logons fail to reach an interactive desktop.
- No clear correlating Windows Event Log errors in many reports, making forensic correlation harder.
- A full server reboot restores functionality — until the next occurrence.
- Incidents often appear at the same local time across multiple machines (reported examples ~14:00 CET), suggesting a scheduled task or synchronized agent action.
Why Trend Micro became the prime suspect
- Removing the WFBS agent has produced immediate resolution in multiple anecdotal cases.
- WFBS behavior monitoring and process‑inspection features can intercept or flag legitimate system behaviors (dwm, termsrv) if not properly trusted/excluded.
- Scheduled scans, engine or pattern updates performed en masse can cause simultaneous CPU or I/O pressure across VMs, producing system responsiveness issues that present as RDP freezes.
- Potential overlaps with Microsoft Defender real‑time protection on server SKUs can create resource contention or double‑scan situations unless Defender is managed per vendor guidance.
The vendor response: 6.7.4065 / 14.3.1342 and what was claimed
Trend Micro support — according to a BornCity reader who opened a case — informed the customer on September 29, 2025 that an agent build 6.7.4065 (with engine/package identifier 14.3.1342) had been pushed and “should” eliminate the freezes. The customer verified the update was applied on the night of September 28 and was told by Trend Micro support that the version was the intended remedy.Official Trend Micro public documentation and the company help center regularly publish hotfixes and KBs for crash/freeze scenarios and advise updating to latest builds and applying server‑targeted exclusions; however, build‑specific public release notes for 6.7.4065 / 14.3.1342 (the precise build numbers referenced by the support rep) may not be widely mirrored in public release bulletins at the time of reporting, which is a common practice for targeted back‑end rollouts or activation‑code driven mitigations. Trend Micro’s public KBs do recommend updating agents and applying server exclusions and provide hotfixes for update/crash scenarios.
What the BornCity reader reported after the update
- Updating to the specified build alone did not immediately solve the freezes for that customer.
- Trend Micro support then performed additional configuration steps (screenshots of which were shared with the reader) and those steps appeared to stop the freezes for at least the two‑day observation window reported; longer‑term confirmation was not available in the original report.
Cross‑checking the claim: what independent sources show
To evaluate the claim we compared three types of information: the BornCity reader report, Trend Micro official KB/readme items, and independent community feedback (forum/Reddit posts).- BornCity (reader report): Trend Micro told the user 6.7.4065/14.3.1342 was intended to fix the RDS freezes, but the reader later said additional steps performed by Trend Micro support were needed for stabilization.
- Trend Micro official documentation: Trend Micro public documentation underscores that updating to the latest agent and applying server‑specific exclusions, as well as hotfixes for known crash/update scenarios, are the vendor‑recommended steps. The help center articles document similar crash/update hotfixes and the general guidance to upgrade agents when BSODs or freezes occur.
- Community threads: Independent administrators have reported mixed outcomes after updating. Some reported the specific build cleared their issue; others reported collateral issues (e.g., Wi‑Fi resume issues, or the need for Trend Micro’s support‑applied configuration steps) or ongoing freezes until exclusions/scan schedules were changed. This suggests heterogeneous effects across different server configurations.
Technical analysis: plausible root causes and why a single build may not be sufficient
The freeze symptom — sessions attached but black screen, input ignored, no matching event log errors — suggests one of the following technical patterns:- Behavior monitoring intercept or block: If the agent’s behavior monitoring hooks treat legitimate actions by dwm.exe, termsrv.exe or related display subsystems as suspicious and intervene, the desktop compositor or RDS service can be effectively interrupted without leaving a clear application‑level error message.
- Resource contention from synchronized tasks: If many WFBS agents in a farm run a full scan, update engine or pattern sync simultaneously (common when agents use synchronized schedules), CPU and disk I/O spikes can starve the display and session host threads, producing effectively frozen RDP experiences.
- Defender + third‑party AV overlap: On Windows Server, if Microsoft Defender real‑time protection is still active while WFBS agent also performs scanning, the double‑scanning or contention can escalate latency and surface unexpected failures; vendor guidance often recommends managing Defender state when third‑party AV is the primary protector.
- False positive / quarantine of a system DLL: An over‑aggressive engine/pattern update could quarantine or block a required DLL (for example termsrv.dll), which would produce abrupt loss of interactive desktop. This is rarer but possible, and administrators are advised to check quarantine logs when symptoms coincide with pattern updates.
Practical remediation checklist (operational, step‑by‑step)
The following sequence is ordered from least to most disruptive. For each step note the operational trade‑offs and how to monitor effect.- Verify the WFBS agent version applied
- Confirm agent and engine/pattern version strings on affected servers (show precise build 6.7.4065 / engine 14.3.1342 if reported by support).
- Collect Trend Micro logs and Windows diagnostic traces for the timeframe of the next occurrence (if you can observe the pattern).
- Apply recommended server exclusions (non‑disruptive)
- Add the following to Trusted Program / Behavior Monitoring exclusions:
- C:\Windows\System32\dwm.exe
- C:\Windows\System32\dwm.dll
- C:\Windows\System32\termsrv.dll
- Wait for policy propagation and verify agents received the change.
- Rationale: prevents the agent from intercepting desktop compositor and RDS processes while leaving full protection otherwise.
- Add the following to Trusted Program / Behavior Monitoring exclusions:
- Stagger scheduled tasks and agent update/check times
- Reschedule full‑system scans and large maintenance tasks to off‑peak windows.
- Introduce random jitter or stagger updates across RDS hosts so they don’t all scan/update simultaneously.
- Rationale: removes synchronized resource spikes that can look like periodic freezes.
- Check Microsoft Defender co‑existence
- Confirm Defender’s state on server SKUs. If Defender and WFBS are both performing active real‑time scanning, coordinate with security teams to put Defender into passive mode or otherwise prevent double‑scanning according to organizational policy.
- Rationale: reduces contention between two real‑time engines.
- If problem persists, open a formal Trend Micro case and supply forensic artifacts
- Provide: Trend Micro agent logs, quarantine logs, Windows Event Logs, Process Explorer / ProcMon traces over the incident interval, performance monitor traces (1–5s sampling), and full server build / KB list.
- Ask for vendor‑applied configuration steps or targeted hotfix application (as happened in the BornCity report).
- Controlled rollback/uninstall — last resort
- If freezes continue and restoration is urgent, plan a small‑scope uninstall of WFBS on one host to confirm whether the agent is the cause.
- If uninstall resolves the issue, do not leave the server unprotected: implement compensating controls (network segmentation, host firewall / jump host access, restoration of agent with vendor help) and document as a temporary emergency measure.
Strengths and limitations of the evidence
Strengths
- Multiple independent anecdotal reports from administrators show immediate restoration after agent removal, which is a strong operational signal implicating the agent.
- Trend Micro support has responded with targeted builds and guidance — evidence the vendor recognizes the interaction vectors and is actively addressing them.
- Vendor documentation already lists server‑specific guidance (exclusions, hotfixes), so the recommended mitigations are consistent with product design and prior KBs.
Limitations and risks
- Public release notes for the exact build numbers (6.7.4065 / 14.3.1342) are not widely mirrored in the vendor’s public bulletins at time of writing; targeted rollouts or activation‑code pushes are common, but that reduces independent verifiability.
- Outcomes vary across environments; the update alone has not universally eliminated the problem according to at least one BornCity reader and other community posts, meaning additional configuration or hotfixes may be necessary.
- Removing endpoint protection as a diagnostic is effective evidence but introduces immediate security risk; any rollback must be temporary and accompanied by compensating controls.
Recommended operational posture for production RDS farms
- Treat this as a high‑impact, medium‑likelihood risk: RDS freezes are business‑critical outages and must be addressed with low tolerance for repeated recurrence.
- Implement the non‑disruptive mitigations first (exclusions, schedule changes, Defender state verification).
- Pilot vendor builds on a small ring of representative hosts; do not push blindly to an entire farm.
- Maintain monitoring that can detect RDP responsiveness regressions (synthetic RDP connect + screenshot + basic input test) so regressions are caught automatically.
- Require a support‑case trace package ready to hand to Trend Micro if unpredictability persists (logs, procmon, perfmon traces, dump files).
- Treat agent updates and security policy changes as high‑impact change items with rollback plans and communications.
Bottom line: does 6.7.4065 / 14.3.1342 “fix” the freezes?
- The vendor‑mediated reality is nuanced: Trend Micro support does identify build 6.7.4065 / 14.3.1342 as a targeted remediation and has deployed it to affected customers, but multiple independent reports show mixed results. In at least one documented case the update alone did not restore stability until the support team also applied additional configuration steps.
- Official Trend Micro guidance and support articles consistently point to three things as most likely to matter: updating the agent, applying server‑specific exclusions for RDS/desktop components, and avoiding scanning/engine update synchronization across a host group. Administrators who only install the agent build without addressing those operational factors may see only partial benefit.
- Independent community reports confirm both successful remediations and lingering problems, so broad claims that a single build will solve every instance are premature. Treat the vendor’s build as an important and necessary step — but not necessarily a sufficient one.
Actionable checklist to take now (concise)
- Confirm whether your affected systems are running Trend Micro WFBS and check the exact agent and engine versions.
- If possible, pilot the 6.7.4065 / 14.3.1342 build on non‑critical hosts — request such a build via support if it’s not yet visible in your management console.
- Immediately add Trusted Program / Behavior Monitoring exclusions for dwm.exe, dwm.dll and termsrv.dll in RDS hosts and apply policy.
- Stagger and randomize scheduled scans and engine/pattern check times across the RDS farm.
- Verify Microsoft Defender’s configuration on each server and coordinate with security teams if Defender needs to be set to passive mode.
- If problems persist, collect logs and open a support case with Trend Micro, supplying performance traces, ProcMon/ProcExp captures and the precise build info.
Final assessment
Trend Micro’s targeted build 6.7.4065 / 14.3.1342 represents a vendor intervention intended to address RDS‑related freezes, and some administrators report success after updating. However, the most persuasive operational pattern in the field shows that the build is often part of a compound remediation: agent update + server exclusions + adjusted scheduling and, in rare cases, vendor‑applied support steps. Administrators should therefore treat the update as an essential first step, but plan for configuration changes and methodical diagnostics if freezes recur. Leaving servers unprotected as a permanent workaround is not acceptable; instead adopt a risk‑managed remediation path that balances high availability and endpoint protection.Note: The technical and operational guidance here is synthesized from a BornCity reader report and follow‑up, Trend Micro public documentation and community reports; administrators should validate all actions in their own test rings and capture detailed diagnostics before and after changes.
Source: BornCity Remote Desktop Server: Does Trend Micro version 6.7.4065/14.3.1342 fix the freezes? | Born's Tech and Windows World
