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PaintTool SAI Development Room
Serious Bug Fix for SAI Ver.1
A serious bug "While saving a canvas, in rare cases the saved file may be lost if another program accesses the saving file." is dicovered in Ver.1.2.5 and earler verions.
As we have not received any reports of this bug to date, we believe that the occurrence rate is low, but we cannot deny the possibility that your valuable works will be lost, so we released the corrected version as a test version.
SAI Ver.1.2.6-Beta.3 32bit - Full Installation (Installer, 2025-01-27, 2.4M)
SAI Ver.1.2.6-Beta.3 32bit - Update Files Only (Installer, 2025-01-27, 1.2M)
SAI Ver.1.2.6-Beta.3 32bit - Full Installation (Installer, 2025-01-27, 2.4M) SAI Ver.1.2.6-Beta.3 32bit - Update Files Only (Installer, 2025-01-27, 1.2M)Technical Preview Version of SAI Ver.2
This is a technical preview version of SAI Ver.2.
Please remember this version will includes some bugs and inconveniences because this version is under development.
Please do not use this version if you want to use stable version.
And, this version requires basic skills for Windows operation.
Please never use this version if you have not basic skills for Windows operation.
Installing and Launching the Application
The distribution is not an installer model. Extract all files and folders from the distribution Zip file, and run sai2.exe directly in the folder of extracted files.
How To Apply Your Software User License of SAI Ver.1 to the technical preview version of SAI Ver.2
If you have a license of SAI Ver.1, you are able to remove the lock of save and load features with your license.
Please download a new license certificate with the system id that got from SAI Ver.2 menu from the license certificate download form, and put it into either of the following folders.
Request for Assistance with Bug Reports
If you encounter a bug, please report it with a description of the bug and the error log if possible. Please note, however, that we do not accept bug reports for outdated versions. Error logs are generated in the folder below with a filename in the format "errlog.sai2.(Date).(LaunchTime).txt". Thank you for your cooperation.
I will read all emails of features request but I will not be able to reply to all request emails because I am one man team for development and customer support. Thank you for your understanding.
- Koji Komatsu - Programmer, President
The distribution is not an installer model. Extract all files and folders from the distribution Zip file, and run sai2.exe directly in the folder of extracted files.
- Extract all files to a location of your choice with "Extract All..." in the context menu for SAI Ver.2 ZIP file(The name format is "sai2-YYYYMMDD-32bit|64bit-ja.zip").
- Launch sai2.exe (Or a file with the name "sai2" and the type "Application") in the extract folder,
How To Apply Your Software User License of SAI Ver.1 to the technical preview version of SAI Ver.2
If you have a license of SAI Ver.1, you are able to remove the lock of save and load features with your license.
Please download a new license certificate with the system id that got from SAI Ver.2 menu from the license certificate download form, and put it into either of the following folders.
- 「<Documents>\SYSTEMAX Software Development\SAIv2」
(The folder included "error" folder and "settings" folder)
Note that the physical location of the "Documents" folder differs depending on whether OneDrive is enabled, as shown below:
- OneDrive enabled: "C:\Users\(username)\OneDrive\Documents"
- OneDrive disabled: "C:\Users\(username)\Documents"
If the license certificate is not recognized when placed in one location, please try placing it in the other.
- OneDrive enabled: "C:\Users\(username)\OneDrive\Documents"
- OneDrive disabled: "C:\Users\(username)\Documents"
If the license certificate is not recognized when placed in one location, please try placing it in the other.
Request for Assistance with Bug Reports
If you encounter a bug, please report it with a description of the bug and the error log if possible. Please note, however, that we do not accept bug reports for outdated versions. Error logs are generated in the folder below with a filename in the format "errlog.sai2.(Date).(LaunchTime).txt". Thank you for your cooperation.
- Documents\SYSTEMAX Software Development\SAIv2\error
I will read all emails of features request but I will not be able to reply to all request emails because I am one man team for development and customer support. Thank you for your understanding.
- Koji Komatsu - Programmer, President
Download PaintTool SAI Ver.2 Technical Preview Stable Version
This is the last stable version before the major renovation.
SAI Ver.2 64bit - 2026-07-02b Technical Preview (ZIP形式, 2.9M)
SAI Ver.2 32bit - 2026-07-02b Technical Preview (ZIP形式, 2.6M)
History
SAI Bristle Definition Bitmap Corrector (ZIP形式, 185K)
| Minimum Requirement (For about a 2000px x 2000px canvas) | |
| Computer | x86 PC (Does support Arm PC) |
| OS | Windows XP/Vista/7/8/8.1/10/11 |
| CPU | Intel Core 2 Duo 1.6GHz |
| Memory | More than 1GB |
| HDD/SSD | More than 20GB free space |
| Video | 1024x768 - 24bit Color |
| Input Device | Pen Tablet (WinTab API and TabletPC API are Supported) |
SAI Ver.2 64bit - 2026-07-02b Technical Preview (ZIP形式, 2.9M) SAI Ver.2 32bit - 2026-07-02b Technical Preview (ZIP形式, 2.6M) History SAI Bristle Definition Bitmap Corrector (ZIP形式, 185K)
This is a program to correct invalid bristle definition bitmaps that can no longer be used from SAIv2 2024-02-22 version.
Originally, SAI silently ignored after the 64th hair points in bristle definition bitmaps. But recently we found that a lot of bristle definition bitmaps with hair points far exceeding 64 points has been circulating. To correct this trendncy, changed the bristle loader to reject incorrect bristle definition bitmaps from 2024-02-22 version.
This program rewrites the hair points after the 64th point to invalid values so that it can be used even after the 2024-02-22 version.
Basic usage is to extract all the ZIP files, run SaiBristleCorrector.exe in the extracted folder, and press the "Execute Correction" button.
Originally, SAI silently ignored after the 64th hair points in bristle definition bitmaps. But recently we found that a lot of bristle definition bitmaps with hair points far exceeding 64 points has been circulating. To correct this trendncy, changed the bristle loader to reject incorrect bristle definition bitmaps from 2024-02-22 version.
This program rewrites the hair points after the 64th point to invalid values so that it can be used even after the 2024-02-22 version.
Basic usage is to extract all the ZIP files, run SaiBristleCorrector.exe in the extracted folder, and press the "Execute Correction" button.
Download PaintTool SAI Ver.2 Technical Preview Major Renovated Version
This version was created by branching off the development project from the 2020-01-07 progress report and undergoing a major renovation.
All bug fixes from the period up to the 2026-07-02 version that could be incorporated into this revised version have been applied.
SAI Ver.2 64bit - 2026-07-30 Technical Preview Major Renovated (ZIP形式, 3.3M)
SAI Ver.2 32bit - 2026-07-30 Technical Preview Major Renovated (ZIP形式, 3.0M)
History
Important Notes
This version may still contain serious bugs. Please take appropriate precautions when using it, such as maintaining multiple backups of your work files.
The following data created in this major update version (or later) are incompatible in older versions:
・Recovery data for works
・Shortcut key settings (saved as separate setting data from that of older versions)
Starting with this major update version, the supported OS is Windows Vista or later, and a CPU with SSE 4.1 support is required.
To everyone who has emailed us to report an issue
Thank you for the many emails reporting issues.
it is currently difficult for us to reply to each email individually with carrying out bug fixing work in parallel. We sincerely apologize, but please understand that the implementation of the fix will serve as our response. We appreciate your understanding.
Bugs reported as of 2026-07-30, that have not yet been fixed.
(Please note that there may be some omissions.)
| Minimum Requirement (For about a 2000px x 2000px canvas) | |
| Computer | x86 PC (Does support Arm PC) |
| OS | Windows Vista/7/8/8.1/10/11 |
| CPU | Intel Core 2 Penryn (SSE 4.1 Required) |
| Memory | More than 1GB |
| HDD/SSD | More than 20GB free space |
| Video | 1024x768 - 24bit Color |
| Input Device | Pen Tablet (WinTab API and TabletPC API are Supported) |
SAI Ver.2 64bit - 2026-07-30 Technical Preview Major Renovated (ZIP形式, 3.3M) SAI Ver.2 32bit - 2026-07-30 Technical Preview Major Renovated (ZIP形式, 3.0M) HistoryImportant Notes
This version may still contain serious bugs. Please take appropriate precautions when using it, such as maintaining multiple backups of your work files.
The following data created in this major update version (or later) are incompatible in older versions:
・Recovery data for works
・Shortcut key settings (saved as separate setting data from that of older versions)
Starting with this major update version, the supported OS is Windows Vista or later, and a CPU with SSE 4.1 support is required.
To everyone who has emailed us to report an issue
Thank you for the many emails reporting issues.
it is currently difficult for us to reply to each email individually with carrying out bug fixing work in parallel. We sincerely apologize, but please understand that the implementation of the fix will serve as our response. We appreciate your understanding.
Bugs reported as of 2026-07-30, that have not yet been fixed.
(Please note that there may be some omissions.)
- Character positioning is incorrect in vertical writing with certain fonts.
- Parts of an image may go missing unnoticed while editing.
- Work recovery may fail midway through the process.
- Layers may appear blank when loading a saved canvas.
We have been unable to reproduce this bug in our environment and are currently gathering information.
- CFF font does not work
At present, CFF (Compact Font Format) fonts are not supported. I plan to implement CFF font support once the bug fixes for the major renovation version currently underway have stabilized.