%PDF-1.4 %âãÏÓ 1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj 2 0 obj << /Type /Pages /Count 2 /Kids [5 0 R 7 0 R] >> endobj 3 0 obj << /Type /Font /Subtype /Type1 /BaseFont /Helvetica >> endobj 4 0 obj << /Type /Font /Subtype /Type1 /BaseFont /Helvetica-Bold >> endobj 5 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 595.28 841.89] /Resources << /Font << /F1 3 0 R /F2 4 0 R >> >> /Contents 6 0 R >> endobj 6 0 obj << /Length 5564 >> stream BT /F2 22 Tf 0.06 0.08 0.12 rg 1 0 0 1 46 789.89 Tm (How to Fix No OS Installed Error on Startup After) Tj ET BT /F2 22 Tf 0.06 0.08 0.12 rg 1 0 0 1 46 762.89 Tm (Booting From Windows Bootable USB) Tj ET BT /F2 11 Tf 0.72 0.14 0.18 rg 1 0 0 1 46 725.89 Tm (TechRounder PDF Edition) Tj ET BT /F1 9.5 Tf 0.36 0.39 0.46 rg 1 0 0 1 46 709.89 Tm (Live article:) Tj ET BT /F1 9.5 Tf 0.36 0.39 0.46 rg 1 0 0 1 46 697.39 Tm (https://www.techrounder.com/how-to/how-to-fix-no-os-installed-error-on-startup-after-booting-from-windows-boot) Tj ET BT /F1 9.5 Tf 0.36 0.39 0.46 rg 1 0 0 1 46 684.89 Tm (able-usb/) Tj ET q 0.82 0.85 0.9 RG 1 w 46 666.39 m 549.28 666.39 l S Q BT /F1 10 Tf 0.24 0.27 0.32 rg 1 0 0 1 46 654.39 Tm (By Vipin PG | Published July 2, 2026 | Updated July 2, 2026 | Format: Guide | 3 min read) Tj ET BT /F2 13 Tf 0.72 0.14 0.18 rg 1 0 0 1 46 631.39 Tm (Quick answer) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 611.39 Tm (The "No OS Installed" error after booting from a Windows USB almost always means the drive's) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 596.39 Tm (partition style \(GPT or MBR\) doesn't match your BIOS boot mode \(UEFI or Legacy\), or the boot order) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 581.39 Tm (wasn't switched back to the internal drive after installation. Fixing it usually takes matching those) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 566.39 Tm (settings correctly, recreating the USB if needed, and rebuilding the boot files from Windows Recovery.) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 541.39 Tm (This error shows up when your PC's firmware can't find a valid, bootable operating system on any) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 526.39 Tm (connected drive - even though Windows may already be installed. It's not a sign that your files are) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 511.39 Tm (gone. It's almost always a mismatch between how the installer wrote the drive and how your BIOS is) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 496.39 Tm (trying to read it. Here's how to track down the exact cause and fix it.) Tj ET BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 468.39 Tm (Step 1: Check If the BIOS Even Detects Your Hard Drive) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 444.39 Tm (Restart your PC and enter the BIOS/UEFI setup \(usually by pressing Del, F2, or F10 during startup\). Go) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 429.39 Tm (to the Boot or Storage section and look for your internal hard drive or SSD in the device list. If it's) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 414.39 Tm (missing entirely, the "No OS Installed" message isn't a boot configuration issue - it's a detection issue,) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 399.39 Tm (and you'll need to check the SATA/NVMe connection or the drive mode \(AHCI vs RAID\) before going) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 384.39 Tm (further.) Tj ET BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 356.39 Tm (Step 2: Match the USB Partition Scheme With Your BIOS Boot Mode) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 332.39 Tm (Most "No OS Installed" errors happen because the bootable USB was created as MBR while the BIOS is) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 317.39 Tm (set to UEFI, or the reverse. In BIOS, check whether your system is set to UEFI, Legacy, or CSM boot) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 302.39 Tm (mode. Then confirm the USB was created to match - GPT partition style pairs with UEFI, and MBR) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 287.39 Tm (pairs with Legacy/CSM. A mismatch here means the firmware simply can't read the installer as a) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 272.39 Tm (valid boot device.) Tj ET BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 244.39 Tm (Step 3: Recreate the Bootable USB With Correct Settings) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 220.39 Tm (If Step 2 revealed a mismatch, the fastest fix is rebuilding the USB. Using a tool like Rufus, select your) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 205.39 Tm (Windows ISO, then explicitly choose the partition scheme \(GPT for UEFI or MBR for Legacy\) that) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 190.39 Tm (matches your BIOS mode before writing the drive. This ensures the installer boots correctly and) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 175.39 Tm (writes the boot files in a format your firmware can actually use.) Tj ET BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 147.39 Tm (Step 4: Fix the Boot Order After Windows Installation) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 123.39 Tm (After installing Windows, the internal drive needs to be set as the first boot device in BIOS - otherwise) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 108.39 Tm (the system may keep trying to boot from the USB or another device and show "No OS Installed" even) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 93.39 Tm (though Windows is fully installed. Go to the Boot Order section in BIOS, move your internal drive \(often) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 78.39 Tm (labeled as "Windows Boot Manager" once installed\) to the top, remove the USB, and save changes.) Tj ET q 0.86 0.88 0.92 RG 1 w 46 42 m 549.28 42 l S Q BT /F1 8.4 Tf 0.42 0.45 0.5 rg 1 0 0 1 46 30 Tm (TechRounder | Page 1 of 2) Tj ET BT /F1 7.2 Tf 0.42 0.45 0.5 rg 1 0 0 1 46 19 Tm (https://www.techrounder.com/pdf/blog/how-to-fix-no-os-installed-error-on-startup-after-booting-from-windows-bootable-usb.pdf) Tj ET endstream endobj 7 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 595.28 841.89] /Resources << /Font << /F1 3 0 R /F2 4 0 R >> >> /Contents 8 0 R >> endobj 8 0 obj << /Length 2875 >> stream BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 789.89 Tm (Step 5: Rebuild the Boot Files Using Windows Recovery Environment) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 765.89 Tm (If the boot order and partition style are both correct but the error persists, the boot configuration data) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 750.89 Tm (\(BCD\) itself may be corrupted. Boot from the Windows USB, choose "Repair your computer," then open) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 735.89 Tm (Command Prompt through Troubleshoot > Advanced Options. Run these commands one at a time:) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 720.89 Tm (`bootrec /fixmbr`, `bootrec /fixboot`, and `bootrec /rebuildbcd`. This rewrites the boot files so the) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 705.89 Tm (firmware can locate your installed Windows copy again.) Tj ET BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 677.89 Tm (Step 6: Verify the Drive Was Initialized Correctly During Installation) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 653.89 Tm (Occasionally, the drive itself was never properly initialized with the right partition table during setup.) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 638.89 Tm (Boot from the USB again, choose "Repair your computer" > Command Prompt, and run `diskpart`, then) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 623.89 Tm (`list disk` and `select disk 0` \(adjust the number to your drive\), followed by `list partition`. You should) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 608.89 Tm (see a proper System partition and a Primary partition. If the layout looks empty or incorrect, you'll) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 593.89 Tm (need to reinstall Windows and let the installer create the partitions fresh, rather than using a) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 578.89 Tm (pre-existing or manually altered layout.) Tj ET BT /F2 15 Tf 0.08 0.1 0.14 rg 1 0 0 1 46 550.89 Tm (Conclusion) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 526.89 Tm (The "No OS Installed" error looks alarming, but it's rarely a sign of data loss - it's almost always a) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 511.89 Tm (mismatch between how the boot media was created and how your BIOS is trying to read it. Working) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 496.89 Tm (through partition style, boot order, and boot file integrity in that order resolves the vast majority of) Tj ET BT /F1 11 Tf 0.14 0.16 0.2 rg 1 0 0 1 46 481.89 Tm (cases without needing a full reinstall.) Tj ET q 0.86 0.88 0.92 RG 1 w 46 42 m 549.28 42 l S Q BT /F1 8.4 Tf 0.42 0.45 0.5 rg 1 0 0 1 46 30 Tm (TechRounder | Page 2 of 2) Tj ET BT /F1 7.2 Tf 0.42 0.45 0.5 rg 1 0 0 1 46 19 Tm (https://www.techrounder.com/pdf/blog/how-to-fix-no-os-installed-error-on-startup-after-booting-from-windows-bootable-usb.pdf) Tj ET endstream endobj xref 0 9 0000000000 65535 f 0000000015 00000 n 0000000064 00000 n 0000000127 00000 n 0000000197 00000 n 0000000272 00000 n 0000000414 00000 n 0000006029 00000 n 0000006171 00000 n trailer << /Size 9 /Root 1 0 R >> startxref 9097 %%EOF