Record the updated device and endpoint
Write down the Galaxy model, installed One UI version and whether the intended receiver is a Windows application or a television connected directly. DeX for PC places a phone environment inside a computer window; direct DeX uses the television or monitor as the receiving display.
Samsung’s current support explicitly attaches the One UI 7 cutoff to DeX for PC. Its cable and wireless television sections have separate compatibility requirements. A failure in the PC application therefore should not automatically be described as a failed HDMI television connection.
Read older instructions in that context
An older guide may still describe installing the PC application and connecting a compatible phone by USB. Before repeating that setup, compare its prerequisites with the updated phone. Reinstalling an old desktop application does not change the mobile software’s documented support boundary.
Samsung points users of affected devices toward Link to Windows for supported PC-connected tasks. That is a different product route with its own capabilities. Do not assume it recreates every former DeX feature or that a successful PC connection verifies television media playback.
Choose the task that remains necessary
If the actual goal is television viewing, consult the direct cable or wireless DeX support for that exact Galaxy model and display. Establish the required receiving technology and supported connection before changing an application account. If the goal is a PC workflow, inspect Samsung’s current alternative guidance.
For help, provide the pre-update and current software versions if known, the receiver type and the task that stopped working. Keep a still-working direct display route separate in the report. These details preserve the difference between a product support change, an unsupported model and a physical connection fault, preventing repeated repairs to a route the updated software no longer supports.