At first running of SAI require the administrator's right on your PC for software installation, you have to run SAI from the administrator user account. Please check following descriptions for each version of Windows.

- Windows 2000/XP
Logon as administrator on your PC and run SAI program, or right click the shortcut of SAI or sai.exe icon and select 'Run as' and 'The following user' with administrator's user name and password.
- Windows Vista/7
Right click the shortcut of SAI or sai.exe icon and select 'Run as administrator' (if your account is limited, The Windows OS will ask the administrator's user name and password.)

If you don't know administrator's user name or password, please contact the owner of your PC.

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.

Please download and install SAI again. If you already have SAI's license, please make sure to download and setup the software license certificate too.
In these case, please make sure to avoid installation to the browser cache folder.

Reference:
Q. SAI application sometimes disappear from my machine automatically.

SAI is Windows application and not run on Macintosh.

These problem occurs in Ver.1.0.x.
Considerable reasons are:

- Software package ("sai-1.0.x.zip") wasn't extracted.
You may use software package ("sai-1.0.x.zip") without extract all files in package, and accessing Zip compressed application directly. If you use Windows XP or later, you can extract sai-1.0.x.zip with right-click menu, or on other versions of Windows, you need to use some archiver software supporting Zip format extraction.

- Only update package ("sai-1.0.xupd.zip") was used alone.
You may use update package ("sai-1.0.xupd.zip") alone, this package is for overwriting on previous installed package and not include any brushes or textures, additionally tool folder is not created so any settings for tools aren't saved. please download and install [Full] package.

These problem occurs in Ver.1.0.x.
You may use software package ("sai-1.0.x.zip") without extract all files in package, and accessed compressed application directly. If you use Windows XP or later, you can extract sai-1.0.x.zip with right-click menu, or on other versions of Windows, you need to use some archiver software which support Zip format extraction.

This is standard security warning for downloaded files from network on Windows XP SP2 or later, you can unlock this message like below.

1. Open SAI installed folder.
2. Right click on file named sai.exe or sai (File type: Application).
3. Select [Properties] on right click menu.
4. Click [Unblock] button on the [General] page.

About SAI Ver.1.1.x.
This problem occurs when SAI is installed in the cache folder of web browser, please refer below topics.
Q.The warning message 'The publisher could not be verified. Are you sure you want to run this software?' was shown. (Ver.1.1.x)

Computers that using Windows XP SP2 or later, help files downloaded from networks is blocked by OS. you can unlock this restriction like below.

1. Open SAI installed folder.
2. Right click on file named help.chm or help (File type: Compiled Windows HTML Help files).
3. Select [Properties] on right click menu.
4. Click [Unblock] button on the [General] page.

About SAI Ver.1.1.x.
This problem occurs when SAI is installed in the cache folder of web browser, please refer below topics.
Q. My machine failed to open help file of this software. (Ver.1.1.x)