Synology NAS Drive Lights Blinking Continuously
Posted: Wed Jun 10, 2026 9:23 am
Drive lights on a Synology NAS normally blink green at different rates indicating a disk drive is reading and/or writing data. Various tasks, running in the background, such as indexing images, videos, audio files, universal search and raid scrubbing cause the lights to blink, often for a few days. Excessive bot traffic can also cause problems. However, in my case captchas were added and the blinking lights continued.
When blinking lights are combined with strained resources where the CPU stays above 80% and MariaDB above 30% for longer periods of time, a week or more, the problem may be security issues due to Universal Plug and Play (UPnP). Enabling and disabling UPnP is a setting in the router's control panel advanced setup. The NAS may use UPnP to open ports for various packages like Media Server.
Keep in mind if a failed drive is replaced, drive lights will blink excessively and it may take extended time to rebuild the data, depending on the volume size.
!IMPORTANT: Disabling UPnP on the router will disrupt Gaming and Voice Chat that rely on Peer-to-Peer hosting or VoIP programs unless firewall rules are created manually. These instructions do not address the Synology Media Server, which may require different settings.
If UPnP is an issue, you must disable it on the router. These changes may be inconvenient because disabling UPnP may require creating firewall rules to permit communication between existing devices, if they do not already exist. Additionally, when adding new devices to the network, rules must be created manually to grant access. However, this inconvenience is well worth the security benefits.
Window11 upgrades have tightened security which makes mapping NAS drives more complicated, while UPnP remains a security problem. When UPnP is enabled adding new network devices is easy but unfortunately comes with some serious security risks.
To disable UnpN on a Synology router:
If you DO NOT have a Synology router UPnP can be disabled by logging in the the router with a browser using the internet interface. The UPnP setting is usually located in the advanced setup section. Uncheck the Enable UPnP box, apply or save the change and ensure the router restarts.
OPTIONAL: Protecting Windows Devices
Windows PCs and laptops can be protected by disabling SSDP and UPnP, when connecting to an unprotected network, i.e. hot spots, that have these features enabled. This prevents malicious software and unauthorized devices from automatically opening network ports, effectively closing a major backdoor that hackers use to infiltrate systems and bypass router firewalls
Disabling these features may also boost performance because it prevents malware or poorly written software from initiating calls to open ports. These features can be re-enabled if you find there is no benefit and the device is always on the same network.
To Begin. press the Windows key + the R Key
Enter services.msc
Scroll down to SSDP Discovery
Double click SSDP Discovery
From the pull down menu click Startup Type window and select disabled
Then click Ok
Scroll down to UPnP Device Host
Double click UPnP Device Host
From the pull down menu click Startup Type window and select disabled
Then click Ok
Please ensure devices reboot after making changes.
When blinking lights are combined with strained resources where the CPU stays above 80% and MariaDB above 30% for longer periods of time, a week or more, the problem may be security issues due to Universal Plug and Play (UPnP). Enabling and disabling UPnP is a setting in the router's control panel advanced setup. The NAS may use UPnP to open ports for various packages like Media Server.
Keep in mind if a failed drive is replaced, drive lights will blink excessively and it may take extended time to rebuild the data, depending on the volume size.
!IMPORTANT: Disabling UPnP on the router will disrupt Gaming and Voice Chat that rely on Peer-to-Peer hosting or VoIP programs unless firewall rules are created manually. These instructions do not address the Synology Media Server, which may require different settings.
If UPnP is an issue, you must disable it on the router. These changes may be inconvenient because disabling UPnP may require creating firewall rules to permit communication between existing devices, if they do not already exist. Additionally, when adding new devices to the network, rules must be created manually to grant access. However, this inconvenience is well worth the security benefits.
Window11 upgrades have tightened security which makes mapping NAS drives more complicated, while UPnP remains a security problem. When UPnP is enabled adding new network devices is easy but unfortunately comes with some serious security risks.
- Bypassed Firewalls: UPnP acts like a valet for your router, allowing any connected device to poke holes in your defenses so incoming internet traffic can reach it.
- Malware and Botnet Infections: Attackers frequently scan the internet for open UPnP ports to hijack smart home devices (like webcams and printers), effectively turning them into massive botnets to launch DDoS attacks.
- No Authentication: The protocol blindly trusts any device requesting changes, meaning a single piece of malicious software running on a PC inside your network can freely expose internal files or systems to the outside world.
- Historical Exploits: The protocol has been central to infamous, large-scale cyber incidents such as the 2016 Mirai Botnet attack and the CallStranger vulnerability.
To disable UnpN on a Synology router:
- Login to the router
- Goto NetWork Center
- Select local Network
- Click on the Primary Network
- Select the Edit tab
- In the pop up window select the Advanced tab
- Uncheck Enable UPnP
- Click the OK Button
- Repeat this procedure for each network
If you DO NOT have a Synology router UPnP can be disabled by logging in the the router with a browser using the internet interface. The UPnP setting is usually located in the advanced setup section. Uncheck the Enable UPnP box, apply or save the change and ensure the router restarts.
OPTIONAL: Protecting Windows Devices
Windows PCs and laptops can be protected by disabling SSDP and UPnP, when connecting to an unprotected network, i.e. hot spots, that have these features enabled. This prevents malicious software and unauthorized devices from automatically opening network ports, effectively closing a major backdoor that hackers use to infiltrate systems and bypass router firewalls
Disabling these features may also boost performance because it prevents malware or poorly written software from initiating calls to open ports. These features can be re-enabled if you find there is no benefit and the device is always on the same network.
To Begin. press the Windows key + the R Key
Enter services.msc
Scroll down to SSDP Discovery
Double click SSDP Discovery
From the pull down menu click Startup Type window and select disabled
Then click Ok
Scroll down to UPnP Device Host
Double click UPnP Device Host
From the pull down menu click Startup Type window and select disabled
Then click Ok
Please ensure devices reboot after making changes.