@ThereseLogeais, I think it is a data entry file. There is both a BM_ProductionTierDistribution file and a BM_ProductionHIstoryTierDist file. The only sage article I found to reinitialize production data entry was for the legacy version but included a Production Entry Tier Distribution File and also a Inv Entry Tier Cost Distribution file. If so, it should not be huge although the history version likely is. The BM_TierCostCalcWork file may correspond to the Temporary Inv Entry Tier Cost Distribution file. A look at the ProductionRestart file might yield a clue.
Old Sage Article.
Possible Resolution:
Note: Reinitializing or recreating data files deletes all records in the selected files and is irreversible. Always make a backup before performing this procedure. If necessary, seek the assistance of a qualified Sage Software business partner or Sage Software Customer Support analyst.
Never reinitialize data files to ""fix"" interrupted updates.
Have all users exit Bill of Materials, and reinitialize the following files:
BMA - B/M Production Entry Header File
BMB - B/M Production Entry Detail File
BMC - B/M Production Entry Tier Distribution File
BMD - Temporary Inv Entry Tier Cost Distribution
BM_01 - Batch Masterfile (if using batch entry)
Delete the batch files (if batch entry is used).
In Windows Explorer, go to ..\Mas90\BMxxx (xxx = company code).
Delete all BMAyyyyy.soa files (yyyyy = the 5-digit batch number. For example, BMA00123.soa represents batch 123).
Rebuild the Bill of Materials sort files.
The following should be true before reinitializing:
The previous Bill of Materials Production Entry update was successful for all entries, and no attempt was made to update Disassembly Entry since then.
Note: Printing is generally OK, but do not reinitialize if 'Yes' was selected when prompted to update.
Loss of existing data entry is acceptable, and the cleared entries can be reentered.
Data entry is empty (Disassembly Entry has been updated and no entries exist). This is typically performed to clear ""ghost"" batches or entries, or to fix files that were damaged after the update.