coming closer, in the log of the agent i found:
2025-06-18 18:09:33.315 [srv 10304] Firewall rule 'Checkmk Agent' had been added successfully for ports [6556]
2025-06-18 18:09:33.317 [srv 10304] File 'C:\ProgramData\cmk_agent_uninstall.txt' is absent, assuming fresh install, legacy pull mode ON
2025-06-18 18:09:33.318 [srv 10304] Reading module config normal
2025-06-18 18:09:33.318 [srv 10304] Processed [1] module(s)
then , after adding an empty version of that file to that location, i’m getting
2025-06-18 18:14:11.761 [srv 6804] Firewall rule 'Checkmk Agent' had been added successfully for ports [6556]
2025-06-18 18:14:11.762 [srv 6804] File 'C: |ProgramData\cmk_agent_uninstall.txt* is too old, assuming fresh install, legacy pull mode ON'
2025-06-18 18:14:11.764 [srv 6804] Reading module config normal
2025-06-18 18:14:11.764 [srv 6804] Processed [1] module(s)
this looks totally weird.
restarting the check mk services removes that file from that location - so if it checks for exitance and then removing it on existence, which leads to assume of fresh installation - how can we have a chance then that registration will be persistent ?
i had the look into the windows agent source, and indeed that file is being refernced there, i.e. being accessed by the windows service. but why ?