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🩹 Patch Scan Error

Endpoint Central Patch Scan Failed RPC Server Unavailable and Scanning Timed Out Fix

Two remarks cause most failed scans in Endpoint Central, and both are really the server saying it could not reach the client properly. Here is how to open the way.

✍️ Technical Anshu🪟 Windows Clients⏱️ 15 minute fix
🎥 Watch the setup that makes scans work from day one in the video

Patch scans and inventory scans in Endpoint Central are on-demand tasks: the console reaches out to the agent right now and waits for an answer. When the reach fails you get "RPC Server Unavailable"; when the answer takes too long you get "Scanning Timed Out". ManageEngine's knowledge base ties both remarks to the same short list — machine state, remote administration, file sharing, the two task ports, and one sneaky server-side trap. Work the list.

Endpoint Central — Patch Management — Scan Status
FINANCE-PC02Failed — RPC Server Unavailable
FINANCE-PC05Failed — Scanning Timed Out
FINANCE-PC06Scan completed
Same scan, three outcomes — the two failure remarks this page fixes
1

For RPC Server Unavailable — Wake the Client Side Up

This remark means the server's remote call found nobody home. Check on the client, in this order:

  1. The computer is switched on and awake during the scan — a sleeping laptop answers nothing
  2. Remote Administration is allowed in the client's firewall. In Windows Defender Firewall, enable the Remote Administration inbound exception (a GPO can set it domain-wide)
  3. File and Printer Sharing for Microsoft Networks is enabled on the client's network adapter
  4. The ManageEngine UEMS - Remote Control service is running on the client — ManageEngine specifically calls this out for scan failures, including machines in remote offices
2

For Scanning Timed Out — Open the Task Ports on the Server

On-demand tasks ride on two ports, and ManageEngine's fix for timeouts starts with adding both to the firewall exception list on the computer where the Endpoint Central server is installed:

  1. 8020 — agent to server communication and the web console
  2. 8027 — on-demand tasks: inventory scan, patch scan, remote control, remote shutdown
  3. Verify from a client with Test-NetConnection -ComputerName SERVERNAME -Port 8027 and confirm TcpTestSucceeded : True
  4. Remember every firewall layer counts — the rule must exist on the server OS firewall and on any network firewall between office segments
3

Remove the Multiple IP Trap on the Server

A classic timeout cause from ManageEngine's own notes: the server computer has multiple IP addresses — two NICs, or a virtual adapter left behind by Hyper-V or VMware. The server answers on one address and listens on another, and scans die waiting.

  1. On the server, list adapters with ipconfig and count how many IPs the machine really has
  2. Disable the unused virtual adapters, or make sure Endpoint Central and DNS agree on the one production address
  3. Restart the Endpoint Central service and re-run the scan on one test computer
4

Prove It With One Computer, Then Scan Everyone ⭐

  1. Pick one always-on desktop near the server and run a manual patch scan on it alone
  2. If it completes, your path is fixed — schedule scans for working hours so machines are actually on, instead of scanning a dark office at midnight
  3. If it still times out while other task types (like remote shutdown) work, collect the server and agent logs for that one machine before contacting support — a single-machine log set gets answers, a fleet-wide complaint does not

Honest expectation: scheduled scans will always have some failures on any real network — people switch machines off. Judge the system by whether powered-on machines scan cleanly, not by a perfect 100 percent.

⚠️ Do not fix RPC errors by disabling the client firewall. It proves the cause in five seconds and creates a security hole in the same five seconds. Add the specific exceptions instead — that is the actual fix.

🎥 See the Console Set Up for Clean Scans

The installation video covers the server, ports and agent basics that keep these errors away.

▶️ Watch Full Video
❓ Frequently Asked Questions

Why do scans fail at night but succeed in the morning?

Because the computers are off at night. On-demand scans need the target awake and reachable. Schedule patch and inventory scans inside working hours, or pair them with wake-up arrangements, and the failure count drops sharply.

RPC unavailable appears for one branch office only. What is different there?

Branch machines sit behind another firewall or router, and the on-demand task traffic (port 8027 and the remote administration path) is not allowed across. For larger branches, a distribution server in that office is ManageEngine's designed answer — scans then run locally inside the branch.

Does the agent not scan by itself on a schedule?

Agents do refresh data with the server periodically, but a scan you start from the console is an on-demand task that needs the live path described on this page. That is why a machine can show fresh inventory yet still fail a manual scan when port 8027 is blocked.

This guide is based on the Technical Anshu video on Endpoint Central installation • Stuck on a step? Ask in the video comments and you will get a reply 🙏