Did Windows 11 26H1 delete your partition?
Short answer: The 26H1 update modifies Windows Recovery Environment (WinRE) partition sizing and, in some configurations, remaps the partition table (the invisible index that tells Windows where each drive section begins). The files on a "missing" partition are almost always still physically present on the drive — only the table entry pointing to them has been lost or overwritten. Recovery is feasible in most cases without professional tools.
How to recover a lost partition after Windows 11 26H1
Step 1: Confirm the partition is missing, not just unmounted
Open Disk Management (right-click Start → Disk Management) and look at the physical disk layout at the bottom of the window. If you see an unallocated block where your partition used to live, the partition table entry is gone. If the space shows as a volume without a drive letter, it is simply unmounted — right-click and assign a drive letter, and your data reappears instantly. Many "lost partition" reports after 26H1 are actually just missing drive-letter assignments, which take ten seconds to fix.
Step 2: Use TestDisk to scan and restore the partition table
TestDisk is a free, open-source tool that reads the raw sectors of your drive and reconstructs the partition table from the data patterns it finds. Download it from cgsecurity.org on a different machine, copy it to a USB drive, and run it on the affected laptop. Select your physical disk, choose the partition table type (usually GPT on modern Windows 11 machines), run Analyse, then Quick Search. In our experience, Quick Search finds most 26H1-affected partitions within two minutes. If it appears in the list, select it, press P to verify the files are visible, and then write the partition table back. Reboot and the partition reappears in Windows Explorer.
For related background on NTFS partition recovery techniques in India, including partition table structure and GPT vs MBR differences, that post covers the fundamentals you need before running TestDisk.
Step 3: If TestDisk Quick Search finds nothing — Extended Search
Run Extended Search in TestDisk, which scans the entire drive sector by sector rather than relying on partition header clues. This takes 20–90 minutes depending on drive size but recovers partitions that Quick Search misses — particularly on NVMe SSDs where the update has overwritten the primary GPT header but left the backup GPT header intact at the end of the drive. TestDisk automatically prefers the backup header in this case. The difference between logical and physical data recovery approaches matters here: Extended Search is still logical work — it does not touch the physical media.
Step 4: The India-specific risk — power-cut mid-update
The most destructive version of this problem we see across Indian cities is when a power cut interrupts the 26H1 update at the moment it is writing the new WinRE partition. The laptop resumes on battery (if it has any charge), but the partition table write is incomplete. The result is a drive where neither the original partition layout nor the new one is fully valid. In these cases, TestDisk often finds multiple overlapping partition candidates, and selecting the wrong one writes an incorrect table. This is the one scenario where attempting recovery without experience makes things worse — stop at the Analyse stage and bring the drive to a professional rather than guessing between candidates. A UPS (uninterruptible power supply) for the home office prevents this entirely.
When to call a data recovery service
When DIY ends
Stop and call a professional if: TestDisk Extended Search shows no candidates; the drive makes clicking or grinding sounds; SMART data (check with CrystalDiskInfo) shows reallocated sector counts above 50; or the laptop shows slow file access times on the remaining partitions. These are signs of underlying laptop hard disk failure alongside the logical partition loss — hardware diagnosis and data extraction should precede any further software recovery attempts.
Typical recovery cost in India
Logical partition recovery (software-level, no physical damage): ₹1,500–₹3,500. Mixed logical and bad-sector cases: ₹4,000–₹8,000. Full cleanroom physical recovery (read head or platter damage): starts at ₹15,000. See the LRW data recovery service page for current scope and turnaround.
A note from the LRW Engineer Team
We see post-update partition loss cases regularly, and almost every one is recoverable if the customer stops using the drive immediately. The mistake that kills recovery chances is continuing to use Windows on the same drive after noticing the partition is gone — every new file written to the "unallocated" space overwrites the old partition's data. If you notice a missing partition today, power the laptop off and contact us before doing anything else.