These problem occurs in Ver.1.1.x.
Considerable reason is that SAI was installed in the cache folder of web browser and some of application files have been deleted.
More details of this problem:
Each files in the cache folder of web browser are deleted regularly, therefore the files of SAI application are deleted too, additionally applications run from the cache folder are limited in execution because of Windows security protection.
When the SAI installer is started, The displayed 'Installation folder' points the installer's location, so if you run the installer directly from downloading link of web browser, the installer is located in the web browser's cache folder. In this case, of course default installation folder points the cache folder, and if you continue installation without changing this location, SAI will be installed in the web browser's cache folder.
Solution for this problem:
You should not install SAI to the web browser's cache folder. Please reinstall SAI to the folder that you created for online software.
If you can not understand this problem, please reinstall SAI with the following procedure.
1. Launch PaintTool SAI installer for full installation.
2. Enter "C:\PaintToolSAI\" to [Installation Folder:] input box.
3. Push [Install] button.
4. Reinstall your software license certificate again if you have license for SAI.
If you didn't install the cache folder of web browser, but trial period has been displayed again.
In this case it may be SAI cannot detects the software license certificate because of the 'System ID' has been changed, please refer following topics.
Q. I already installed my software license certificate and using SAI, but suddenly trial period has been shown again.