"Clock surfing" can break your license
Application Note 601
As with many time controlled software licensing management systems, the MacroVision FLEXlm license manager used in Polar's Si8000/9000 and SB200 software products keeps a watchful eye on the system clock to check for signs of "clock surfing" (also known as "date surfing" or "clock tampering"), i.e. users altering the computer clock (usually setting the clock back to a date earlier than the software cut off date) in order to extract more life out of time limited software. The situation is by no means unique to Polar; "clock surfing" can affect many other time critical applications, including email clients and anti-virus software. In the case of "floating" or server-based licenses the client and server clocks must coincide to within a few hours of each other.
The license manager will not, of course, prevent legitimate changes to the system clock, such as minor adjustments to set the correct time or time zone or altering the date for daylight saving. However, if the license manager detects significant changes in the system clock (regardless of how or why the clock has changed) the license manager will refuse to issue licenses on that machine.
This behaviour is by design and applies to every type of license based on the MacroVision FLEXlm licensing scheme (electronic, software key and server licenses). The software licensing manager is performing correctly and issuing a new license or software key will not reactivate the software — the problem lies with the host PC and not the license or software key.
In one recent example, a customer called to say that not only would the Si8000 not run on his PC, but all the department's PCs refused to allow the Si8000 to run, each claiming the clock had been set back. It turned out the department had received a batch of new machines, all of which had been built in the future with a system date set to 2009!
In many cases, the only solution is to reformat the machine's hard disk and reinstall the operating system and all software. In cases where the clock has been changed by only a few days the licensed software may reactivate after the latest date/time detected by the license manager.
Avoid making major changes to your computer clock. There are several (low cost) software solutions to prevent accidental date adjustment.
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© Polar Instruments 2006. Polar Instruments pursues a policy of continuous improvement. The specifications in this document may therefore be changed without notice. All trademarks recognised.