Summary: On two clients, server share writes slow to a crawl with NOD32 real-time protection. When file system protection is disabled or the share excluded, speeds resume to normal. NOD32 updated to latest version and definitions updated. Detail: Beginning on 18th November, a client reported a significant slowdown in their line-of-business application which stores data on a SBS 2003 server using a standard Windows (SMB) share, that is, not using a client-server database. Application software support personnel indicated it was due to "network communications problems." I conducted extensive analysis and found no problems, though I noticed copying a sample folder with large files from a PC-to-Server was noticeably slower than copying Server-to-PC. Application software support was contacted again and they were not able to find much, except that some improvement could be made by running the workstation in Safe Mode w/ Network. I ran another copy test and found even further PC-to-Server slowness (8x slower). At this point, I experimented with disabling all NOD32 protection. Disabling NOD32 on the PC helped very little, but disabling it on the server made copying almost as fast, that is a 1000% improvement. I then found I could go into NOD32 setup and configure an exception to File System protection to exclude a sub-folder of the share used for the application data files. This provided the same improvement. The client reports that the issue appears to be resolved. This of course is just a workaround. About 10 days later, a different client had performance issues that, short story, were alleviated by excluding the data share. Data: Test and time files copy. J:\a-test folder copied on acctg2 PC, from server share to acctg2 folder 139MB in 168 files, 10 folders 0:11.5 - Copy from server to acctg2 1:32.1 - Copy from acctg2 to server Turned off ESET on PC 0:05.7 - Copy from server to acctg2 1:31.4 - Copy from acctg2 to server Turned off ESET on server and PC 0:06.7 - Copy from server to acctg2 0:07.4 - Copy from acctg2 to server Turned ON ESET on server and PC, with exclusion on File System protection for ACI and ACI32 folders 0:08.4 - Copy from server to acctg2 0:09.2 - Copy from acctg2 to server 92.1 seconds / 9.2 seconds = 10.1 or about 10x speed improvement.