A tax season does not wait for a slow computer. This post is for accountants, bookkeepers and small shop owners who keep their ledgers, GST returns and invoices on a Windows PC and worry about what a big Windows update might do to them. You will get a folder-by-folder list of what to copy first, a simple dated-copy habit, and a one-minute test that proves your backup opens when you need it.
Which accounting files should I back up before a Windows update?
Short answer: Copy four groups of files: Excel ledgers and working sheets, GST return and portal downloads, invoice and bill folders, and the full data folder of your accounting software, if you use one. Put the copies on an external drive that stays unplugged afterwards, with the date in the folder name. Then open one copied ledger to check it works.
Why do updates call for a backup?
Many Windows updates pass quietly. But updates restart the PC, change system files and sometimes bring bugs. In June 2026, for example, Microsoft confirmed that an update, KB5094126, made the Recycle Bin show internal file names and stopped some third-party apps from opening Office apps. Accountants often use tools that link to Excel, so such a problem lands directly on their desk.
The bigger reason is timing. Windows 11 26H2 began rolling out on 29 September 2026, in phases, so your PC may be offered it on any day. Your files are likely to be fine. A backup means that, if they are not, you lose an hour and not a quarter of work.
The checklist for an accountant's PC
For Tally Prime, copy the whole data directory, not only exported reports. If something already looks damaged, read our Tally Prime data file recovery guide before you open the file again.
How to make the copy, step by step
- Close Excel and the accounting software, so that no file is open while you copy.
- Plug in an external drive and make a folder named with today's date, for example Backup 09-10.
- Copy the folders from the table above into it. Copy, do not move.
- Open one ledger and one invoice PDF from the external drive.
- Eject the drive and keep it somewhere safe, not in the same bag as the computer.
Repeat the exercise weekly. Keep the last three or four dated copies instead of overwriting one. Mistakes are sometimes noticed late in accounting, and an older copy can rescue the work. Our guide to backup software for Indian small businesses covers automatic options, and the restore test guide shows how to prove a backup works.
Never keep your only backup on the same computer or the same drive as the ledgers. A single drive failure takes both away.
A note on cloud copies
A cloud folder is handy as a second copy, but check two things. First, client data may carry a confidentiality duty, so use an account that only you control. Second, a synced folder mirrors deletions, so it is not a safe history on its own. See cloud versus external drive backup for the trade-offs.
Power cuts, deadlines and office dust
Power cuts and voltage dips can damage a file that is being saved. Put the PC on a UPS (a small battery backup) and keep the charger connected on a laptop during updates. Large updates also fail on patchy broadband, so let them finish on a steady line. Filing deadlines do not move for a slow PC, so do your copies before the last week of the month and never during it. Dust inside a cabinet PC can slow the drive and heat up the machine, so a yearly clean is a cheap precaution.
When to get help
- An Excel ledger shows a repair message, opens blank or reports that the file is corrupt.
- Your accounting data folder is missing after an update.
- The PC restarts repeatedly and does not reach Windows.
- The hard drive clicks, freezes the PC or takes minutes to open a folder.
Our data recovery service handles damaged drives and lost folders, and we start with a diagnosis. In Hyderabad we offer a doorstep service, and the charge is ₹149 doorstep visit fee, waived when you approve laptop repair with us. Stop saving new files to a drive that you think is failing, because every write can overwrite the files you want back. The quote for recovery comes after diagnosis and is shared for approval before any work.
A note from the LRW Engineer Team
Give your backup one fixed day, for example every Friday evening after the day's entries. Copy the folders, open one file from the copy and write the date on the drive. Ten minutes a week is the cheapest protection a small practice can buy. It also makes every Windows update far less frightening.