Error 10010 is listed in the B-Tree Filer Error Codes as: ‘The index file wasn’t correctly closed after the last use. This could have unforeseen consequences for future use of the associated files. A reconstruction cannot be avoided.’ This error occurs most often with files that do not have index files. The header record is damaged when the file is not closed correctly and reports that it should have an index file the next time an attempt is made to open the file. Use the REBUILD Tool, if available, to correct the header record, or Reconstruct the damaged file. File Client_M.Dat is the most common occurence of this error. It can be caused if a user turns the computer off while in the Activities module.