QNAP NAS Error Code 62: How to Fix It

Q: What does QNAP Error Code 62 mean?

QNAP Error Code 62 means that your NAS cache pool — typically made up of one or more SSD drives used to accelerate storage performance — has reached its full capacity. When the cache is full, the NAS can no longer store new data in the fast SSD cache layer, which can degrade overall read/write performance.

Q: Will QNAP Error Code 62 cause data loss?

Error Code 62 itself does not directly cause data loss. However, if you are using Write Back caching mode and the cache is full, there is a small risk of data loss if the NAS loses power before the cache is flushed to the main storage pool. Using a UPS and switching to Read Only cache mode reduces this risk significantly.

Q: How do I clear the cache pool on a QNAP NAS?

Log into QTS, open Storage Manager, go to Cache Acceleration or Tiered Storage, and click the 'Flush Cache' or 'Clean Cache' option for your cache pool. This writes all cached data back to your primary HDDs and frees up space in the SSD cache. The process typically takes 5–30 minutes depending on how full the cache is.

Q: How much SSD cache do I need for my QNAP NAS?

QNAP recommends sizing your SSD cache at roughly 1–5% of your total working data set for read caching, and 10–20% of your expected daily write volume for write-back caching. For most home and small office setups, a 250GB to 1TB NVMe or SATA SSD provides adequate caching. If Error Code 62 keeps recurring, your cache is undersized for your workload and you should upgrade to a larger SSD.

Q: Can I add a second SSD to expand my QNAP cache pool?

Yes, many QNAP NAS models support multiple SSD cache drives. You can install a second compatible SSD and then either expand the existing cache pool (if your QTS version supports it) or remove the old cache pool and create a new, larger one using both SSDs. Check your specific QNAP model's specifications on qnap.com to confirm how many cache drives are supported and which SSD form factors (M.2 NVMe, M.2 SATA, or 2.5-inch SATA) are compatible.

Abstract

QNAP Error Code 62 means your NAS cache pool has reached its maximum capacity and can no longer accept new cached data. This typically affects systems using SSD caching (via QTS Storage Manager) where the designated cache drives are completely filled. While rated as a medium-severity issue, leaving it unresolved can slow down NAS read/write performance and may eventually interrupt normal storage operations.