MYOB Classic files are synchronised to Bi4Cloud using a MYOB supplied ODBC connection.
There have been a few issues associated with ODBC and the cache settings
1. Terminal Server Installations and ODBC Cache
The BI Connector gets a disk cache error from MYOB when a user using the connector is a Terminal Server session. The c:\b4cloud\ir_intranet_docs\irDBimportLog.txt has an error
ERROR: Could not add Table Customers from a1 as Customers ERROR
 [MYOB ODBC] Error initialising the disk cache
Disk cache is used by the MYOB ODBC when the datafile is being read and the system memory needs to write data to the C:\MYOBODBC\Cache directory. So the connector may function fine on smaller files but larger file ie greater than 100mb can fail because they need to write to disk cache. The failure is because MYOB cannot determine the cache directory in terminal server environments. The fix is to copy the OpenRDA.ini file to the users directory as below
The full article on the MYOB site is here
2. Larger MYOB files ie 1.0Gb and larger
For company files that exceed the 1GB size, the data extract will eventually fail as the MYOB ODBC driver runs out of allocated memory.
The error message is this
ERROR : Could not add Table JournalRecords from a1 as table JournalRecords ERROR  [MYOB ODBC]Disk Cache file size limit has reached
The workaround is -
1. Edit the C:\Windows\openrda.ini file and increase MAX_SIZE to 512 for CacheOptions:
Save and close the file.
2. Ensure all users are out of MYOB
3. Close any other add-on applications that use MYOB ODBC
Re-run the data extraction.