① Starting Point: The Issue Began After a System Upgrade
We received a support ticket from user Eike Kollmorgen. He was using a TESmart HKS0402A2U KVM switch, but after connecting it to a Mac Mini 2018 running macOS Sequoia 15.3.2, he suddenly found that the mouse was stuck in the top-left corner and would not move, and the keyboard stopped responding entirely, while everything worked perfectly on Windows 11.
This unexpected situation caused significant disruption to his daily work.
② Real Confusion: Compatibility Issues Rarely “Announce” Themselves
It appeared to be a typical compatibility issue, yet the tricky part was:
• Windows worked normally
• The issue only appeared after upgrading macOS
• Only the keyboard and mouse were affected
This selective malfunction made it reasonable to suspect that a change between the system and firmware had triggered an anomaly.
③ Our Diagnostic Process: From Firmware Inspection to User-side Verification
Our support team initially determined that it might be a compatibility issue between the KVM and macOS Sequoia, and provided the user with the firmware upgrade package, upgrade instructions, and the Windows upgrade tool download link.
After updating the firmware as instructed, both the mouse and keyboard initially returned to normal.
However, after he upgraded macOS again to the latest version, a new issue appeared:
The mouse worked fine, but the keyboard could no longer be recognized.
We continued troubleshooting and ultimately confirmed that it was an occasional compatibility issue triggered by the interaction between the keyboard and the system.
④ Actions and Improvements: This Investigation Helped Us Refine Our Compatibility Strategy for Older Devices
To prevent similar situations in the future, we implemented several measures:
• Strengthened compatibility testing for older devices during major macOS updates
• Updated the firmware and upgrade tool documentation to make the process clearer
• Compiled more complete macOS keyboard-recognition cases and added them to the FAQ
• Added cross-system compatibility notes to the tool download page to reduce user issues
Ultimately, after the user switched to a USB wired keyboard, the KVM resumed normal operation on both macOS and Windows.
⑤ Customer Feedback
Throughout the entire process, the user remained very patient and even expressed understanding when the support response was delayed due to the Lunar New Year holiday.
After the issue was resolved, he confirmed that the ticket could be closed.
Such trust and positive feedback from users mean a great deal to us.
⑥ Conclusion: Every Compatibility Issue Is an Opportunity to Improve the Experience
This incident reminded us once again that in an ever‑evolving operating system environment, the compatibility of older devices deserves more attention than we often expect.
Each troubleshooting session and each small issue triggered by a system update is an opportunity to improve product experience and strengthen user trust.
Technology advances, but the user experience should never be left behind.
