: A single-user license allows installation on up to two computers for the same individual, though only one can run SketchUp at a time. Activation Process To authorize your copy of SketchUp 2016:

To authorize SketchUp Pro 2016, you must use a Classic License

Hunting for a SketchUp 2016 serial number is like chasing a ghost. Instead, grab SketchUp 2017 Make (free & legal) or use the current Free web version. Your computer—and your conscience—will thank you.

: If you receive an "Invalid" error, try manually typing the code instead of pasting, as extra spaces can sometimes cause issues.

: For network installations, license info is sometimes stored in a file named activation_info.txt located in C:\ProgramData\SketchUp\SketchUp 2016 (Windows) or /Library/Application Support/SketchUp 2016/ (Mac). 2016 activation_info.txt not working - SketchUp Forums

First, using cracked serial numbers violates copyright law and software license agreements. Legal repercussions can include fines or lawsuits, even for individual users. Second, keygens and cracked versions are common vectors for malware, including ransomware and keyloggers. A 2017 study by security firm Cybereason found that over 50% of cracked software contained hidden malicious code. Third, unauthorized versions lack updates and support, leaving users vulnerable to bugs and compatibility issues.