Support

Contact a human

There is no ticket portal, no chatbot, and no phone tree. There is an email address, and a person reads it.

SUPPORT_EMAIL_PLACEHOLDER

What helps us help you: which app and version, your Windows version, the file's size and type (for FastSheet), what you did, and what happened instead.

Please don't send us your spreadsheet. The whole point of these apps is that your data stays on your PC — that shouldn't stop being true the moment you need help. The size and type of the file is almost always enough. If we ever genuinely need more, we'll ask, and you can say no.

Install

System requirements

• Windows 10 or Windows 11, 64-bit.
• Microsoft Edge WebView2 runtime, which ships with Windows 11 and is present on virtually every up-to-date Windows 10 machine. If it is missing, the installer will tell you.
• No admin rights needed for a per-user install. No internet connection needed to run either app.

PinRail (free)

1. Download PinRail-Setup.exe from the PinRail page. It is about 2 MB.
2. Your browser may warn that the file is uncommon — choose Keep. Then run it. Windows will show the SmartScreen notice; here's why and what to do.
3. Follow the installer. PinRail starts and puts an icon in your system tray.
4. Flick your mouse to the top edge of the screen and the dock slides out. Open its settings to change the edge, size, theme, or whether it starts with Windows.

FastSheet (paid — not on sale yet)

When checkout opens, this is the flow:

1. Buy from the FastSheet page. Checkout is handled by Lemon Squeezy, our merchant of record.
2. You receive an email with your download link and your licence key. Keep the key — it is your proof of purchase.
3. Run the installer. Same SmartScreen notice applies until we are code-signed.
4. Open FastSheet, paste your licence key once to activate. This is the only moment the app touches the network, and it sends only the key. After that it runs entirely offline, and does not re-check on every launch.
5. Drag a spreadsheet in.

Only download our software from this site. We can't vouch for a copy from anywhere else.

The SmartScreen warning

What you'll see

A blue window: "Windows protected your PC" — "Microsoft Defender SmartScreen prevented an unrecognised app from starting."

What to do

1. Click More info — a small link in the dialog, easy to miss.
2. The publisher and app name appear, with a new button.
3. Click Run anyway.

If your browser blocked the download first, choose Keep (Edge) or Keep anyway (Chrome) in the downloads bar before running it.

You don't have to take our word for it

You are being asked to run an unsigned program from a studio you've never heard of. Healthy scepticism is correct. So:

• Scan it. Upload the installer to VirusTotal and see for yourself. Note that unsigned installers from small publishers do sometimes draw heuristic flags — that is what "unknown publisher" costs.
• Watch the network. This is the claim that matters most for FastSheet, and it is the easiest to test: open a file with a firewall monitor running. PinRail cannot make network connections at all; FastSheet is limited by policy to a single address, api.lemonsqueezy.com, and only when you activate a licence. Any other destination is blocked outright by the app itself.
• Read what we promise. The privacy policy spells out exactly what leaves your machine and what doesn't.

When our certificate arrives, the warning disappears for new installers. Nothing else about the apps changes.

Uninstall

Both apps uninstall like any normal Windows program. No account to close, no "are you sure you want to leave" theatre.

Remove the app

1. If you're removing PinRail, quit it first: right-click its tray icon and choose Quit. (If you turned on "start with Windows", switch that off in its settings first — it's the tidy way to remove the startup entry.)
2. Open Start → Settings → Apps → Installed apps.
3. Find FastSheet or PinRail, click the … menu, choose Uninstall.

Remove leftover settings

Uninstalling removes the program. If you also want your settings gone:

• PinRail keeps your pins and settings in %APPDATA%\pinrail\ — two small files, pins.json and settings.json. Paste that path into File Explorer's address bar and delete the folder. Keep it if you might reinstall; your pins come back.
• FastSheet keeps its settings and, if you activated one, a local record of your licence in its own app data folder. Removing the app removes them. Your licence key still works if you reinstall — keep the email.

Your spreadsheets are never touched. FastSheet is read-only and only ever reads what you open, so uninstalling it cannot affect a file of yours.

Known limits

This list exists because a tool that hides its edges is a tool you find them in at the worst moment. These are measured, not guessed, and they are the basis for what "as described" means in our refund policy.

What FastSheet is for

• It is a read-only viewer. It never edits, never writes to your file, has no formulas and no charts. To change a file you still need Excel.
• "Large" means heavy in megabytes, not infinite in rows — the workbooks that make Excel freeze. A real 131 MB accounting workbook (1.36 GB uncompressed) opened in about 10 seconds on a laptop.
• Rows have a ceiling, and it isn't ours. A single .xlsx worksheet holds at most 1,048,576 rows — that is the file format's limit, and no viewer can lift it. FastSheet's own safety ceiling is 2,000,000 rows in memory; a file beyond it is shown truncated and says so, rather than quietly dropping rows.
• How long a full sheet takes. We filled a sheet to that format ceiling — 1,048,575 rows across 8 columns, 8.4 million cells, 42.5 MB — and it opened in about 13 seconds (measured range 10.5–14.3 s over four runs on a 16 GB laptop). We quote the range rather than our best run, because the best run is the one that flatters us.
• Speed follows cell count, not megabytes. The 42.5 MB full sheet above takes about 13 seconds, while the 131 MB accounting workbook — three times the size on disk, but heavy with formatting rather than cells — took about 10. File size is not a speed predictor, and we don't treat it as one.
• It reads the file into memory. It is tuned for big files, not for tens of gigabytes of data. Your RAM is the real ceiling.

Where the display differs from Excel

In every case below the underlying value is correct — what differs is how it's presented.

One case where a number can be wrong

We would rather flag this loudly than have you find it. If a CSV file uses a comma as the decimal separator (writing 1,5 to mean one and a half), the column statistics — sum and average — may read that comma as a thousands separator and produce a wrong total. The cells themselves display correctly; only the computed statistic is affected. If your CSVs are written that way, check the totals by hand. We are fixing it; until then, it is on this page.

Troubleshooting

Windows says "unknown publisher"

Expected, for now. See above.

FastSheet says my licence key is invalid

Activation needs a network connection for that one moment — check you're online, and paste the key with no stray spaces. If it still fails, email us your order number and we'll sort it out. This is the only step that ever needs the internet; if you're offline you can still open files, you just can't activate.

A file opens slowly

.xlsx costs far more than .csv for the same data — the format has to be unzipped and its XML parsed, where a CSV is little more than splitting lines. That cost is inherent to the format, not something we've hidden.

What drives the wait is how many cells there are to parse, not the file's size on disk (see known limits). A completely full sheet takes around 13 seconds. Very large files are also bounded by your RAM, since the file is held in memory.

PinRail doesn't slide out

Check which edge it's docked to in its settings, and that it's running (look for the tray icon). If another app also claims that screen edge, they can fight over it — moving PinRail to a different edge is the quick fix.

Something else

Email SUPPORT_EMAIL_PLACEHOLDER. If you found a bug, you have done us a favour, and we'd like to know.

See also: Privacy Policy · Terms · Refund Policy