download camtasia

Let's start!
First of all, download camtasia from here: https://filehippo.com/download_camtasia_studio/
After that turn off your internet and
then install camtasia.

add this to your Hosts file:
host file location will be: C:\Windows\System32\drivers\etc\hosts
open you with file with notepad using admin privileges.

127.0.0.1 activation.cloud.techsmith.com
127.0.0.1 oscount.techsmith.com
127.0.0.1 updater.techsmith.com
127.0.0.1 camtasiatudi.techsmith.com
127.0.0.1 tsccloud.cloudapp.net
127.0.0.1 assest.cloud.techsmith.com

Now go to C:\ProgramData\TechSmith\Camtasia Studio 9 and open RegInfo.ini (you have to "Show hidden folders" to find it!)
Delete everything you see and replace it with this:

[RegistrationInfo]
ValidationData3=1
RegistrationKey=key_here.   XXX(serial number)
RegisteredTo=user_here.  XXX(user name)
ValidationData1=
ValidationData2=1

Change "key_here" with one of these keys:

AAM4UMUFLBCURCCCHCLF2C987
UVVDCGZBCL7QCCCAHKXDM25FD
GWAM4FUU5ZCMXCCHC44AC9R3E
5CVY6A9CCCM2WAKHHCCEK8E29
Y69CC7CWMBDYCYA5MF5CX6A4B
ASHCYWNTECD7VCCCAHLXCDF3C

Change "user_here" with the username you want to use.

Close and save the file.

Right click > Properties > Check Read only