Closed-beta install guide
Lambrary is an Excel add-in that gives LAMBDA functions IntelliSense (parameter hints, autocomplete, descriptions) and a library tool to browse, document, share, and export them.
Setup takes about two minutes.
Windows 10/11 · Microsoft 365 or Excel 2024 (64-bit). Unblock the zip, extract, and follow the steps below.
Lambrary64.xll.The beta package contains a single file, Lambrary64.xll, for 64-bit Excel: the supported, tested build.
Not sure which you have? In Excel: File → Account → About Excel. The version line ends in "32-bit" or "64-bit". The vast majority of Microsoft 365 installs are 64-bit.
If you're on 32-bit Excel, this package won't load; the wrong-bitness file fails silently. A 32-bit build exists but isn't part of the beta; email support@lambrary.com and I'll send it.
Windows blocks files received from the internet by default, and until you clear that, Excel refuses to load the add-in. Unblocking the zip before you extract is the easy way; the file inside comes out already cleared.
.zip → Properties.You'll get Lambrary64.xll. If no Unblock checkbox appeared, the download was already cleared, so just extract.
Lambrary64.xll you extracted → OK.A new ribbon tab labeled Lambrary appears between your other tabs.
Test. Refers to: =LAMBDA(x, x*2). OK.=Test( and pause. A tooltip should appear showing the parameter x.0.2.0-beta.10).If all four work, you're set.
From beta.8 onward, Lambrary can update itself: with Check for Updates on, an Update button appears on the tab when a newer build is published. If you'd rather update by hand, or you're coming from an earlier build, replace the file:
Lambrary64.xll with the new one: same filename, same location, overwrite.You don't need to untick/retick the add-in unless the filename changed.
The diagnostic log is the most useful thing you can send.
%APPDATA%\Lambrary).Tell us:
The log records Lambrary's own activity: load, scan, every ribbon click, every dialog open and close, and the type of any error that occurred. It does not contain LAMBDA names, parameter names, formula text, descriptions, or values from your workbook. Counts and structural flags only.
If a bug can only be reproduced with proprietary content, I'll ask for it explicitly.
.xll from disk.If Excel later complains the add-in file is missing, click Yes when it offers to remove the broken reference.
Documentation left in your workbooks. If you documented any LAMBDAs, Lambrary stored that text as hidden __doc defined names inside those specific workbooks, not in the add-in. Uninstalling can't remove them (the add-in has no record of which files they're in), but they're harmless: hidden, text-only, and ignored by Excel. To clear them from a workbook, run Lambrary tab → Remove Docs before uninstalling, or delete them by hand via Show Doc Names → Name Manager.
"This add-in is from an unverified publisher". This is expected. Lambrary isn't code-signed during the beta. Click Run anyway or Trust when prompted. (If a managed/work machine blocks unsigned add-ins outright, try a personal machine.)
The Lambrary tab doesn't appear. Quit and reopen Excel. If it still doesn't appear, re-check that the entry is ticked in the Add-ins dialog (Step 3, item 5). If absent, send the log.
Tooltips don't show when I'm typing. Lambrary uses Windows accessibility hooks to detect formula editing. Some locked-down enterprise machines disable UI Automation via group policy. Try a personal machine if you have one.
Excel reports a missing file on startup. You deleted the .xll without unticking it first. Click Yes to remove the reference; Excel starts cleanly next time.
Lambrary is in closed beta. Please don't redistribute the .xll. Feedback is the whole point of this beta; even "no problems, the IntelliSense just works" is useful signal.