One USB, every rescue tool, no reinstall between machines
XDA ran a piece this week on the diagnostic USB the writer keeps in a laptop bag, and it started a familiar argument in the replies. Which loader? Which cleanup tool? Which hardware profiler? The right answer is not one app. It is a portable PC diagnostic USB with a stack of tools that boot on any machine you plug them into.
The seven picks below cover the four jobs a technician actually needs from a rescue drive: boot into a broken PC, read every hardware sensor, check disk health without touching Windows, and clean the machine before handing it back. Every app runs from a stick with no installer footprint on the host.
What to look for in a portable diagnostic app
Four criteria separate a rescue tool from a nice-to-have.
- Runs without touching the host filesystem. A tool that writes to
C:\is not portable. - Boots or loads on any hardware from 2015 forward. Older BIOS, newer UEFI, both.
- Reads what you need without an internet connection. The broken machine may not have working networking.
- Sits on the USB in under 500 MB. A rescue kit that fills a 64 GB drive is one tool, not seven.
Quick comparison
| App | Best for | License | Storage on USB | Runs from |
|---|---|---|---|---|
| Ventoy | Multi-boot loader | Free, open-source | 20 MB | Any USB |
| Hiren’s BootCD PE | Windows PE rescue | Free (non-commercial) | ~1.4 GB | Ventoy or ISO burn |
| MediCat USB | All-in-one PE + Linux | Free (donation) | ~22 GB | Dedicated stick |
| SystemRescue | Linux boot rescue | Free, open-source | ~900 MB | Ventoy or ISO burn |
| Ultimate Boot CD | Vendor diagnostic bundle | Free | ~700 MB | Ventoy or ISO burn |
| HWiNFO Portable | Hardware profiling | Freeware | ~15 MB | Any USB, live Windows |
| CrystalDiskInfo Portable | SMART disk health | Free, open-source | ~10 MB | Any USB, live Windows |
The apps
1. Ventoy, the multi-boot base
Ventoy is the reason a single USB can carry every other tool on this list. Copy any bootable ISO to the drive and Ventoy lists it in a boot menu. No reflashing between tools, no dedicated stick per ISO. Version 1.1.x supports secure boot, persistence, and both BIOS and UEFI targets.
Where it falls short: the first-time install still wipes the target drive. Recovery of files from a stick before Ventoy install has to happen elsewhere.
Pricing: free, MIT license.
Platforms: Windows and Linux install, boots into any OS ISO.
Download: ventoy.net
Bottom line: start every portable diagnostic USB here. Everything else on this list sits on top of Ventoy.
2. Hiren’s BootCD PE, Windows repair in a WinPE shell
Hiren’s BootCD PE rebuilt the old Hiren’s brand around a modern Windows PE environment. Recovery tools for registry, partition, password, and driver cleanup all run from a live Windows shell. Two decades of technicians still reach for it because the toolset covers the messy 20% cases scripting cannot.
Where it falls short: the download is around 1.4 GB. Corporate use requires per-tool license checks, since the bundle mixes free and licensed software.
Pricing: free for personal and home use.
Platforms: Windows PE.
Download: hirensbootcd.org
Bottom line: the go-to when the host Windows install still boots but is broken enough that you need offline tools.
3. MediCat USB, the all-in-one bundle
MediCat USB is a preassembled diagnostic USB image with dozens of tools already dropped into Ventoy. Windows PE, Hiren’s, Kaspersky Rescue, Malwarebytes, disk imaging, benchmarking. If assembling a stack from scratch is not your idea of a good Saturday, MediCat ships it prebuilt.
Where it falls short: the total image is roughly 22 GB. It needs a dedicated 32 GB stick or larger, and a couple of the bundled tools are shareware trials, not truly free.
Pricing: free, donation supported.
Platforms: Ventoy-based, boots WinPE and Linux ISOs.
Download: medicatusb.com
Bottom line: the fastest way to a working diagnostic USB if you accept the disk footprint and light shareware content.
4. SystemRescue, the Linux rescue baseline
SystemRescue is the go-to Linux-based rescue live boot. It carries GParted, TestDisk, PhotoRec, ddrescue, ntfs-3g, and modern kernels for both new NVMe drives and older SATA. Text mode boots on the pickiest hardware.
Where it falls short: the interface is CLI-first. Anyone expecting a GUI-driven repair flow will bounce off it.
Pricing: free, open-source.
Platforms: Linux live boot.
Download: system-rescue.org
Bottom line: the pick when Windows will not boot at all and you need to recover files off the disk before reinstall.
5. Ultimate Boot CD, vendor-tool bundle
Ultimate Boot CD collects vendor diagnostic tools (Seagate SeaTools, WD Diagnostics, MemTest86+, hardware-specific stress utilities) into one bootable image. It has been around since 2003 and remains the fastest way to get an OEM-blessed disk or RAM test running.
Where it falls short: the interface is older than most technicians using it. Some bundled tools are legacy 32-bit binaries.
Pricing: free, distributor mirrors.
Platforms: BIOS and UEFI boot.
Download: ultimatebootcd.com
Bottom line: the pick when you need vendor tools to prove a drive or RAM stick is bad, not just that the OS thinks so.
6. HWiNFO Portable, live-Windows hardware profiling
HWiNFO Portable runs inside a working Windows install and reads every sensor and firmware version the machine exposes. GPU, CPU, VRM temperatures, memory timings, PCIe link state. It is the tool of choice when the OS boots but the customer says something is running slow.
Where it falls short: it is Windows-only in portable form. A Linux equivalent (lm-sensors, lshw) exists but is not from this project.
Pricing: free for personal use, paid Pro license for commercial deployments.
Platforms: Windows portable, no install required.
Download: hwinfo.com
Bottom line: carry it for the diagnostic call where the machine boots and the customer just wants to know what is going on.
7. CrystalDiskInfo Portable, SMART disk health at a glance
CrystalDiskInfo Portable reads the SMART attributes of every drive attached to a live Windows install and flags the ones trending toward failure. Reallocated sector counts, wear leveling for SSDs, temperature. Two clicks to know whether the drive is worth saving.
Where it falls short: it is read-only on SMART. It reports failure but does not clone or repair.
Pricing: free, open-source.
Platforms: Windows portable, no install required.
Download: crystalmark.info
Bottom line: pair it with SystemRescue’s ddrescue when the SMART numbers say to migrate the drive today.
How to pick the right one
If you are starting fresh, the honest answer is that no single app on this list solves a broken PC alone. The real portable diagnostic USB is a Ventoy stick with Hiren’s BootCD PE, SystemRescue, and HWiNFO Portable on it, plus one of the vendor bundles like Ultimate Boot CD for RAM and disk certification. Add CrystalDiskInfo for the friend-of-a-friend home visits where the customer just wants to know if the drive is dying.
If you want to skip the assembly, MediCat USB ships all of this in one 22 GB image on a dedicated stick.
Pick HWiNFO Portable as a solo add-on to any daily-carry USB. It weighs 15 MB and answers half the “is this normal?” questions on the spot.
FAQ
Can Ventoy boot both BIOS and UEFI machines? Yes. Ventoy supports legacy BIOS and UEFI (with and without secure boot enabled) on the same stick.
Do I need separate USBs for each rescue tool? No. Ventoy holds every ISO on one drive and lets you pick from a boot menu. That is the point.
Is Hiren’s BootCD PE the same product as the original Hiren’s BootCD? Different projects, same brand lineage. The original Hiren’s BootCD stopped in 2012. Hiren’s BootCD PE is a modern rebuild by a different maintainer, based on Windows PE.
How large should my portable diagnostic USB be? 32 GB minimum. 64 GB or 128 GB is more comfortable once you add spare Windows install ISOs, driver caches, and a portable antivirus.
Is any of this legal to use on a customer’s machine? Hiren’s BootCD PE and MediCat USB are free for personal, non-commercial use. Paid technician deployments must license the bundled Windows PE and any commercial tools separately.
