I can assure you that is very normal especially for niche software.

I deal with this on a corporate setting a lot .

Thats why I asked the TS, whether they knowingly use this software via pirated means.

like standard sop for scaming.. better check first before making action

1.) How much does the software cost?
2.) Do you really need that software for your business or is there any alternative.
3.) If you really need that software, just pay the license.
4.) If you cannot afford that software, find the alternative.
Simple as that.

I can assure you that is very normal especially for niche software.

I deal with this on a corporate setting a lot .

Thats why I asked the TS, whether they knowingly use this software via pirated means.

niche engineering software only knows if the software manages to communicate with server (something crackers would take care off), most of the time when you get a letter like that its because you torrented something, opened it and it was fake, basically something they use to try and get rid of pirates even though the software/video is fake.

A lot of niche software companies do not bother trying to fight the pirates, when people cannot afford to buy your software its not going to help trying to go after them, so if its a company from the US, its something they would already know but any company that knows you use their software to make money but not pay for it will obviously go after you, but this rarely happens and usually caught when audited.

So just audit your own company to show that such claim is not true. If you did find the software, just claim that the install was not authorised and removed (you can prove this if your company doesnt use said CAD to make products, by showing what you use for your products).

Most of the time these letters are scams/fakes, basically legit company that release fake stuff to make people who want to pirate download it, its easy and cheap to have thousands of seeds for it and torrents let you track who your seeds and peers too so when you try and search for their product, the fake pops up in a favourable way.

The reason i say this is because only 1 PC was said to use it when it seems his company has many PCs, so this seems to me like the case of an unauthorised install or fake for tracking. This is one reason for tight control over your network and PCs and the only way if this is a legit claim is to have a proper audit that shows otherwise (including that you never touch their product when you make yours) and that such a thing was unauthorised and to thank them of exposing a vulnerability in your network.

You lucky didn't kena raid. When I was much younger (late 90's), I used to work for Business Software Alliance (BSA). Based on whistle blower, we raid offices.

Armed with a team of Penguat Kuasa (gomen officers), lawyers, tech (me and some other computer guys) and a court warrant.

We removed all the staffs from the office, check every PC for software. Then ask the company to produce the license. e.g. If got 20 MS Windows and 15 MS Office, they need to produce the said amount of licenses. Failure to produce the licenses, each offence is fined RM20K.

One of the office I raided got over 50 PCs. Fully installed with Windows, Office, Adobe suite (it is a publishing house).

Lawyers sit down with the boss to settle. That day cannot settle. We bring lorry and confiscate all the PC as evidence, pending court case.

After that, the lawyers bring us to hotel for buffet. Give us RM300 for a day's job.

but how did they know your company name/company address to send you a letter ?
are you using fixed IP ?
still think some kind of scam.