Plant ERP History Still Lives in Lotus 1-2-3 Workbooks

Lotus 1-2-3 was the unofficial second ERP

On many lines, the purchased MRP or shop-floor package never held every working model. Planners, cost accountants, and process engineers kept parallel Lotus 1-2-3 notebooks: exploded BOMs for engineering change reviews, machine-load calendars, scrap and yield trackers, overtime cost builds, and supplier price ladders that never made it into the formal system of record.

When the plant finally cut over to a full ERP or MES, those notebooks were rarely deleted. They were copied onto new file servers, burned to optical media, zipped into change-control tickets, and left in folders named for SKUs, work centers, or fiscal years. The binary format—not the business meaning—is what makes them hard to open on Windows 11 today.

Four Lotus extensions you will actually find

Plant archives almost always mix generations. DOS-era .wk1 files show up in the oldest cost and capacity models. Windows-era .wk3 and .wk4 workbooks dominate mid-1990s production and finance shares. Later SmartSuite .123 notebooks appear where a site stayed on Lotus longer than the rest of the company.

Treat each extension as its own sample set. Convert a handful of .wk1, .wk3, .wk4, and .123 files into a separate output folder, open the XLSX results in Excel, and confirm part numbers, quantities, dates, and totals before you run the full plant tree. Lotus Converter is built for those Lotus 1-2-3 spreadsheet inputs—not Quattro Pro .wb* workbooks.

Match each workbook type to a modern use

A conversion pass plant IT will approve

Mount the archive read-only. Copy the Lotus tree to a controlled working volume. Run Lotus Converter 6.1.0 offline on that copy so nothing leaves the plant network. Write XLSX, CSV, and PDF into a new folder tree—never overwrite the originals—and keep the per-file conversion log with source path, output path, format, and timestamp.

Start with the free 10-file trial on a representative mix of extensions. If the sample looks right, license Standard for unlimited local conversions. Add Conversion Library Plus ($29.95 one-time, same MSI) when planners need to search and preview the converted plant library on that PC instead of hunting opaque filenames in File Explorer.

What "done" looks like for a plant archive

Done is not a single heroic overnight batch. Done is: originals sealed, outputs named consistently by plant and year, conversion logs filed where quality and audit can find them, and the hot set of BOMs, routings, and cost models already opened once in Excel by the people who will be asked for them next.

After that, a recall investigation, product-line carve-out, or supplier price challenge becomes a retrieval problem—not a “does anyone still have Lotus?” problem.