Microsoft OLE type file for Mac
File type: Database file
A .otlb file is a Microsoft OLE type library file for Mac. It stores definitions that describe OLE objects, interfaces, methods, and data types.
The file belongs to Microsoft's OLE software technology and is used as supporting metadata rather than as a document intended for direct editing.
File type category:
Database file
Date updated: September 27, 2026
Microsoft OLE type library files contain information that allows software to discover and communicate with OLE automation objects. The definitions can describe an object's available interfaces, methods, properties, and the data types those members use.
OLE DB is a set of COM-based interfaces that expose data from a variety of sources. OLE DB interfaces provide applications with uniform access to data stored in diverse information sources, or data stores. These interfaces support the amount of DBMS functionality appropriate to the data store, enabling the data store to share its data.
This format is associated with Microsoft's OLE implementation for Mac and was used by software that provided or consumed OLE components. It is associated with legacy Macintosh software and is not commonly used on current platforms.
Open a .otlb file with the Microsoft software or legacy Mac application that created or uses it. It is generally a supporting file, so it may not produce useful output when opened on its own.
Current operating systems may not provide a program that can open this legacy Mac format directly. Do not expect a general text editor or database application to display its contents correctly.
A .otlb file is not normally converted because it contains type-library definitions rather than user documents or database records. There is no general-purpose conversion that turns it into a useful modern document.
If the associated legacy application is still available, use that application's own export or migration features, if provided. Otherwise, preserve the file with the application and system environment it requires.
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