This usually happens if you have a new replacement key or if the license was used on more devices than allowed [5.6].
This is the most common source. Look for an email sent immediately after your purchase [5.3, 5.4, 5.9]. Ccleaner pro license key
How to Enable CCleaner License After Purchase ... - LeetCode This usually happens if you have a new
Your files could be encrypted and held for ransom [5.7]. How to Enable CCleaner License After Purchase
If you bought a physical copy, the key is usually on a card or sticker inside the box [11]. Activation Steps for PC and Mac
If you have a Pro Plus or Premium license, the same key can be used across multiple PCs, Macs, and Android devices [5.18, 5.21].
Activating your license transforms the free version into the Professional edition instantly. On Windows: and navigate to Options > About [5.8]. Click on Upgrade to Pro or Register/Enter Key [5.8, 5.14].