If you've lost your email, you can use the official CCleaner License Lookup to retrieve it using your registered email address [5.3, 5.6].
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]. Ccleaner pro license key
This is the most common source. Look for an email sent immediately after your purchase [5.3, 5.4, 5.9]. If you've lost your email, you can use
While many websites claim to offer "free" or "cracked" license keys, using them carries significant risks. Official guidance from CCleaner Support warns that these keys are often bundled with: If you've lost your email
To move your license to a new computer, simply install the free version on the new device and enter your existing key [5.16].