In theory, you need Visio to open and edit a VSD or VSDX file because it is the default file format of Visio, a popular diagramming software from Microsoft. Some diagramming software are developed with a compatibility with both VSD and VSDX formats, allowing you to open or edit a VSD or VSDX file without Visio.
You can even open a VSD file without installing any diagramming software thanks to the existence of online diagramming tools like Lucidchart and Gliffy. Typically, they will convert the VSD/VSDX format into XML or other formats they support.
Here are how to open VSD or VSDX file without Visio.
Open VSD file using draw.io
draw.io is a free online diagramming tool that has a compatibility with VSD and VSDX format so you can use it to open or edit VSD/VSDX files. It is probably the best free diagramming tool. In addition to free, this tool is also released as an open source software. Desktop version is also available in case you are more comfortable working with desktop-based tool.
To open a VSD/VSDX file using this tool, visit its website (if you prefer to use the online version). You will be greeted by a pop-up dialog that ask you to whether create a new diagram or open an existing diagram file. To open an existing diagram file simply click the Open Existing Diagram button and select your file.
Open VSD file using SmartDraw
SmartDraw is another diagramming software that has a compatibility with VSD and VSDX file. You can save your work into VSD format and vice versa, open a VSD file. SmartDraw is a comprehensive diagramming software which you can use to create any sort of diagrams. From flowchart diagram, UML, infographic and so on. Unlike draw.io, SmartDraw is a paid tool. You have 7 days to try this tool for free. SmartDraw is available in web version and desktop version.
To open a VSD file using the web version of SmartDraw, visit the website of SmartDraw web version. You will be greeted by a pop-up that ask you to create an account or login with your account if you already have one. To start opening a VSD file, click the Visio File button on the Import section on the left panel.
Select your VSD file(s) and click the Import Selected Files button to import it to SmartDraw.
Wait a moment until SmartDraw is done importing your files. Once done, select one of the imported files to open it.
Open VSD file using Lucidchart
Lucidchart is a powerful online diagramming tool. It also has a compatibility with Visio where you can either open or save your works into VSD or VSDX format. Lucidchart is freemium tool, meaning that you can use it for free, but with some restrictions. The free version of Lucidpress only allows you to open VSD files without editing ability. Trial version is available in case you just need to edit a VSD or VSDX file once.
To open a VSD file using this tool, first visit its website and create an account. You can login with your Google account. Click the Import button on the Lucidchart file manager and and select Import Visio.
Choose your VSD file and click the Import button.
Wait a moment until Lucidchart is done importing your file and click the Done button. To open the imported files, return to file manager. Hover your mouse over a file you want to open and click the Open button.
Open VSD file using Gliffy
Gliffy is HTML5-based online diagramming tool. It also has a compatibility with Visio to allow you either open a Visio file — be it VSD or VSDX — or save your work into a Visio file. Gliffy is a paid tool. You have 7 days to use it for free during the trial period, which you can make use of if you only need to open and edit a Visio file once. Before being able to use this tool, you need to create an account first. Or, you can login with your Google account. Visit its website and click the Try it free button to use the trial version.
To start opening a Visio file, click the File menu and select Import.
Wait a moment until Gliffy is done importing your file and you will be taken directly to the editor page.