2.2.4 EFS Cache Timeout
The EFS cache timeout field is specified as follows:
Key: Software\Policies\Microsoft\Windows NT\CurrentVersion\EFS
Value: "CacheTimeout" or one of the special values in [MS-GPREG] section 3.2.5.1.
Type: REG_DWORD.
Size: Equal to size of the Data field.
Data: This field is intended to be used in conjunction with a flag to flush the cache on timeout (specified earlier as 0x00000010). The implementation MUST either support both the CacheTimeout field AND the flag to flush the cache on timeout, or neither the CacheTimeout field nor the flag to flush the cache on timeout. This value MUST be expressed as a number of minutes, and the value SHOULD be no less than 5 and no greater than 10080 (that is, one week).<5>
If the client supports this option but the option is not present, the client SHOULD use a default value of 480 (that is, 8 hours).