Solution: The portable version requires Microsoft Visual C++ Redistributables. Install the VC++ 2015-2022 x86/x64 runtimes from Microsoft. These are system-wide dependencies that no portable app can bundle.
When you click "Mount," Windows will ask for Administrator permission. Grant it. The portable version will temporarily install the driver; when you close PowerISO, you can optionally unload the driver via the menu. poweriso90x86x64portable7z verified
After downloading, use VirusTotal.com to scan the PowerISO.exe file. A clean, verified portable should have 0/70 detections. If it shows 1 or 2 generic "PUA" (Potentially Unwanted Application) flags, that might be a false positive. If it shows 10+ detections, delete it. Guide: Understanding and Using PowerISO 9