The Symantec Endpoint Protection 11 client is fully supported on the Windows XP Embedded (XPe) platform as of SEP 11 MR2.  All features of SEP, including antivirus, will function normally. However, there are three important caveats:

1. There are minimum XPe OS module requirements (that may be heavy for certain embedded environments)
   a. Internet Explorer 6, TCP/IP Networking, COM Base, IP Security Services, NDIS, NDIS User-mode I/O Driver, and OLE Dialog Interfaces.
2. This will have the standard SEP client footprint in terms of disk, RAM, CPU, etc. (which is very heavy for certain embedded environment, especially in terms of disk space)
3. SEP does not use the Embedded APIs that allow operation in conjunction with the write filter feature, so it would have to be disabled

SSEP for Windows XP Embedded 5.1 (XPe Agent) is a purpose-built agent for Windows XP Embedded that has a much smaller footprint (especially disk) and supports the write filter. There are, however, two important limitations of which administrators should be aware:

1. SSEP for Windows XP Embedded 5.1 clients are not compatible with the management components of SEP 11 (Symantec Endpoint Protection Manager).  They cannot be managed from the SEPM or receive their content updates from it.
2. At present, the SSEP for Windows XP Embedded 5.1 product updates its AV definitions once per week.  Customers who wish to see this improved can vote for the corresponding Connect Forum Idea (enhancement request) Increase Frequency of Updates: SEP for Windows XP Embedded