If your real need is portable diagramming—not necessarily Visio itself—there are excellent, legal portable alternatives that work with Visio files (.vsdx).
: It can work, albeit slower. Cons : High memory usage, potential crashes with complex diagrams, and anti-virus false positives. microsoft office visio 2013 portable
If you need to (e.g., network diagrams, flowcharts, floor plans, or process maps), here are legal options: If your real need is portable diagramming—not necessarily