Same exact problem. Also have Synology.
Can we verify the thumb issues are those files solely on NAS, I have many files also on local HD.
I keep missing thumbs after rebuilding as well, and today had quite a hang up while MC did something to build Tiles.
Interestingly enough, today I yanked my dual-port Intel NIC, and I am averaging 60mb/s R/W now as opposed to 30mb/S and overall better DPC performance so I don't think it's NIC related. I also just updated to a new Synology DSM version, but the problem persists.
1082802: 7940: Database: CThumbnailsDatabase::GetThumbnails: Creating object
1082818: 7940: Database: CDataHolder::Load: Field: Thumbnail Offset Medium; Files: 448110; Pointer bytes: 1792588; Data bytes: 409720; Elapsed ms: 20.269
1082849: 5056: Database: MCDB::Save: Start
1082849: 5056: Database: MCDB::Save: Saving (bCleanDB: 0, bForce: 0)
1082896: 5056: Database: CMediaFileIOSave::Load: Saving: C:\Users\x64\AppData\Roaming\J River\Media Center 20\Library\mediafiles.jmd
1082896: 5056: Database: CMediaFileIOSave::Load: Saving: C:\Users\x64\AppData\Roaming\J River\Media Center 20\Library\field (bookmark).jmd
1082912: 5056: Database: CDataHolder::Save: Field: Bookmark; Elapsed ms: 12.855
1082912: 5056: Database: CMediaFileIOSave::Load: Saving: C:\Users\x64\AppData\Roaming\J River\Media Center 20\Library\field (skip count).jmd
1082927: 5056: Database: CDataHolder::Save: Field: Skip Count; Elapsed ms: 8.157
1082927: 5056: Database: CMediaFileIOSave::Load: Saving: C:\Users\x64\AppData\Roaming\J River\Media Center 20\Library\field (last skipped).jmd
1082927: 5056: Database: CDataHolder::Save: Field: Last Skipped; Elapsed ms: 8.817
1082927: 5056: Database: CMediaFileIOSave::Load: Saving: C:\Users\x64\AppData\Roaming\J River\Media Center 20\Library\view state temporary (index).jmd
1082958: 5056: Database: MCDB::Save: Finish (109 ms)
1082974: 5056: Database: MCDB::Save: Start
1082974: 5056: Database: MCDB::Save: Saving (bCleanDB: 0, bForce: 0)
1082974: 5056: Database: MCDB::Save: Finish (0 ms)
1082990: 5056: General: CSkinnedMainFrame::OnTimer::IDT_CHECK_MAXIMIZE_RECTANGLE: Start
1082990: 5056: General: CSkinnedMainFrame::OnTimer::IDT_CHECK_MAXIMIZE_RECTANGLE: Ideal maximize rectangle doesn't match last maximize -- resizing to correct
1082990: 5056: General: CSkinnedMainFrame::OnTimer::IDT_CHECK_MAXIMIZE_RECTANGLE: Finish (0 ms)1083114: 7236: Sharing Plugins: CHTTPListenerWorker::HandleConnection: Start
1083114: 7236: Sharing Plugins: VHTTPMessage::ParseBody: Start
1083114: 7236: Sharing Plugins: VHTTPMessage::ParseBody: Reading 681 bytes from message body
1083114: 7236: Sharing Plugins: VHTTPMessage::ParseBody: Finish (0 ms)
1083114: 7236: Sharing Plugins: CHTTPListenerWorker::HandleRequest: TCP: 192.168.3.251: POST:
http://192.168.3.199:52100/ContentDirectory/control1083114: 7236: Sharing Plugins: CDLNADeviceServerWorker::ProcessPost: Start
1083114: 7236: Sharing Plugins: CContentDirectoryService::HandleControlFunction: Start
1083114: 7236: Sharing Plugins: CContentDirectoryService::HandleControlFunction: Action: Browse
1083114: 7236: Sharing Plugins: CContentDirectoryService::Browse: Start
1083114: 7236: Sharing Plugins: CContentDirectoryService::Browse: Browse BrowseDirectChildren for 1031