Adobe no longer sells CS3. They don’t support it. They don’t care if you download abandonware? Wrong. Legally, they still own the copyright. The official position is: CS3 users must upgrade to Creative Cloud.
Assuming you have acquired a legitimate, licensed copy of Illustrator CS3 and built your own portable version (using tools like VMware ThinApp), here is the optimal workflow. Adobe Illustrator CS3 Portable -
D:\PortableApps\
\Adobe Illustrator CS3\
\App\ (Virtualized program files)
\Data\ (User settings, brushes, swatches)
\Illustrator_Portable.exe
\Fonts\ (Place custom fonts here to avoid OS installation)
No, unless you absolutely must.
The era of portable legacy software is fading. Modern operating systems (Windows 11, macOS Ventura and later) have hardened security that actively blocks the virtualization techniques used by portable repacks. Furthermore, Adobe has released Illustrator on the web (beta) and Illustrator for iPad—true cloud-native solutions that don't require installation at all. Adobe no longer sells CS3
The biggest annoyance: You cannot double-click an .ai file to open it. Since the software isn't installed, the OS doesn't know what to do. You must always: Open Illustrator first, then use File > Open. Assuming you have acquired a legitimate, licensed copy
Your main PC crashes. You boot from a Linux live USB or a Windows PE environment. You have no registry, no C:\ drive. A portable CS3 is the only way to open a corrupt .ai file to rescue your work.