Troubleshoot installation and upgrades

Start with the earliest failing layer. Preserve the first error and the environment state before retrying; repeated partial installs or upgrades can hide the original cause.

Symptom	Likely causes	Safe diagnostic	Resolution and verification
Designer cannot load a system connection	Missing/invalid Connections.json, blank DisplayName, zero ConfigNum, unresolved database key or driver problem	Validate JSON and selected key; test database resolution under the interactive identity	Correct the profile/driver, reopen Designer and verify the intended environment
Service starts then stops	Missing -c/-n, database/schema unavailable, account lacks ProgramData/database rights	Inspect Windows service definition and startup/system logs without exposing credentials	Correct parameters/rights/schema, start once and verify process/status communication
API port does not listen	Port conflict, wrong service instance/key, listener startup failure	Check the configured port and owning process; review API Service startup log	Free/change the port, restart API Service and test a controlled REST Flow
Files/configuration disappeared after install	Environment-owned ProgramData was overwritten by defaults	Stop processing and compare secure backup to current files	Restore reviewed files, reapply only required release assets, then revalidate
Post-upgrade modules fail to load	Schema/version mismatch, missing dependency or module-stream conversion issue	Preserve the exact module/error and compare applied release steps	Stop services, correct/roll back using the release plan, then retest isolated modules
Flow succeeds but external delivery is missing	Outbound send is asynchronous	Inspect Transport Logs, attempts and next-attempt time	Correct the Transport/dependency and use the appropriate transport retry path

Collect release/version, bitness, connection key (not secrets), service name/state/parameters, first error, database-update record, relevant Flow/Transport identifiers and a sanitised log excerpt. Continue with service troubleshooting for established installations.