NetTool.Win32.Calc-Dnet is a detection for distributed.net clients. It is a legitimate software that may be dropped by malware without authorization. If you have deliberately installed the software that is being detected as Riskware then you may exclude the application's folder from scans.
Based on the settings of your F-Secure security product, it may block the file from running, move it to the quarantine where it cannot spread or cause harm, or ask you to select an action.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
NetTool.Win32.Calc-Dnet.g detects the v2.9001.477 Win32 executable version of the Distributed.net client. This client is used to implement a "distributed computing" network, where it uses the host system's idle CPU time to process parts of a given project. This usually are typically complex mathematical challenges, e.g. signal processing or decryption.
This software has been known to be modified/dropped by malware, unauthorized installation of this program on a system should be investigated.