The short answer
- AI is Adobe Illustrator’s native image-design format that preserves editable artwork and multiple artboards, but exported or older-version copies may not retain all original document data.
- Open an AI file in an updated Adobe Illustrator installation; Adobe officially supports opening and placing AI files. On Windows or macOS, use File > Open and select the file. Another Adobe application may use the embedded PDF representation when “Create PDF Compatible File” was enabled, but that view should not be treated as proof that Illustrator-native editing data will remain editable. On a phone, do not assume compatibility unless the chosen application explicitly supports the AI variant or its embedded PDF representation.
- Treat an AI file from an unknown source as potentially risky. AI documents can contain complex nested content, and Adobe’s March 2026 bulletin fixed Illustrator memory-corruption flaws requiring user interaction that could allow arbitrary code execution, plus out-of-bounds reads. Use an updated, least-privileged application and avoid opening unexpected attachments. This evidence concerns parser risk; it does not mean every AI file contains executable behavior.
AI File: Identify, Open, Assess and Convert Adobe Illustrator Artwork
An AI file is the native artwork format used by Adobe Illustrator. It can retain Illustrator editing data, multiple artboards, linked artwork, permitted fonts, ICC profiles and, when selected, an embedded PDF representation. AI has changed over time: legacy files may be PostScript-based, while later variants can use a PDF header with Illustrator-specific markers.
Keep the AI file as the editable master until work is complete, then export the needed delivery format. Exporting or reopening a non-native format can lose Illustrator document data. A PDF-compatible AI file improves interoperability but does not guarantee native editability outside Illustrator. Saving to an older Illustrator version can also change data: unsupported features may be lost, and transparency may be discarded or flattened.
How to open it
Open an AI file in an updated Adobe Illustrator installation; Adobe officially supports opening and placing AI files. On Windows or macOS, use File > Open and select the file. Another Adobe application may use the embedded PDF representation when “Create PDF Compatible File” was enabled, but that view should not be treated as proof that Illustrator-native editing data will remain editable. On a phone, do not assume compatibility unless the chosen application explicitly supports the AI variant or its embedded PDF representation.
Open an AI file in an updated Adobe Illustrator installation; Adobe officially supports opening and placing AI files. On Windows or macOS, use File > Open and select the file. Another Adobe application may use the embedded PDF representation when “Create PDF Compatible File” was enabled, but that view should not be treated as proof that Illustrator-native editing data will remain editable. On a phone, do not assume compatibility unless the chosen application explicitly supports the AI variant or its embedded PDF representation.
Keep the AI file as the editable master until work is complete, then export the needed delivery format. Exporting or reopening a non-native format can lose Illustrator document data. A PDF-compatible AI file improves interoperability but does not guarantee native editability outside Illustrator. Saving to an older Illustrator version can also change data: unsupported features may be lost, and transparency may be discarded or flattened.
File safety
Treat an AI file from an unknown source as potentially risky. AI documents can contain complex nested content, and Adobe’s March 2026 bulletin fixed Illustrator memory-corruption flaws requiring user interaction that could allow arbitrary code execution, plus out-of-bounds reads. Use an updated, least-privileged application and avoid opening unexpected attachments. This evidence concerns parser risk; it does not mean every AI file contains executable behavior.
An unknown sender, a name ending in two extensions, or contents that do not match the extension — check before you open it.
Converting it
Keep the AI file as the editable master until work is complete, then export the needed delivery format. Exporting or reopening a non-native format can lose Illustrator document data. A PDF-compatible AI file improves interoperability but does not guarantee native editability outside Illustrator. Saving to an older Illustrator version can also change data: unsupported features may be lost, and transparency may be discarded or flattened.
Convert a copy, never the original, then compare quality, metadata, and layout against what you started with.
Common questions
What is an Adobe Illustrator AI file used for?
An AI file is Illustrator’s native artwork format. It is used to retain editable Illustrator data and can preserve multiple artboards, linked artwork, permitted fonts, ICC profiles and an optional PDF representation.
How do I open an AI file in Adobe Illustrator?
Use an updated Illustrator installation, choose File > Open, and select the AI file. Adobe officially lists AI for opening and placing in Illustrator.
How do I open an AI file on Windows?
Install or update Adobe Illustrator on Windows, then open the AI file from File > Open. If another application shows only embedded PDF content, do not assume it preserves native Illustrator editing data.
How do I open an AI file on a Mac?
Use an updated Adobe Illustrator installation on macOS and select the AI file through File > Open. PDF-compatible content may improve viewing in other Adobe applications, but native editability is not guaranteed there.
Why will my AI file not open or display correctly?
The file may be a different Illustrator generation, may lack an embedded PDF representation needed by another application, or may contain features that changed during older-version saving or export. Try the updated Illustrator application and preserve the original file while investigating.
Should I use an AI file or a PDF file for editable artwork?
Use AI as the master while Illustrator editing must be preserved. Use the required delivery format after editing; an embedded PDF representation improves interoperability but should not be assumed to preserve all Illustrator-native data.
How do I convert an AI file to PDF while retaining vector artwork?
Open the AI master in Illustrator and export or save the required PDF after editing. Retain the original AI because reopening a non-native export may not recover all original Illustrator document data.
What is lost when an AI file is converted to PNG?
PNG is a delivery export rather than the Illustrator-native editing master. Illustrator may be unable to retrieve all original document data when that exported file is reopened, so keep the AI source.
Is an AI file received by email safe to open?
Its extension alone cannot establish safety. Open an expected file only with an updated, least-privileged application; Adobe has fixed Illustrator parsing flaws that required user interaction and could lead to code execution or memory disclosure.
What does Create PDF Compatible File mean for an AI file?
It stores a PDF representation inside the AI document to improve compatibility with other Adobe applications and embeds permitted fonts, though not necessarily every font. It does not guarantee preservation of native Illustrator editing data in a PDF-only application.
Related formats
Sources
How to save artwork in Illustrator · Adobe, official format developer documentation
Supported file formats for Illustrator · Adobe, official product documentation
PRONOM detailed report: Adobe Illustrator CC Artwork 17-23 signatures · The National Archives (UK), authoritative digital-format registry
PRONOM detailed report: Adobe Illustrator 9.0 signatures · The National Archives (UK), authoritative digital-format registry
PRONOM detailed report: Adobe Illustrator 88 v1 signatures · The National Archives (UK), authoritative digital-format registry
Security Updates Available for Adobe Illustrator | APSB26-18 · Adobe Product Security Incident Response Team