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How can you override this error?

AV sync errors do not prevent ripping. They are warnings (sometimes false) about issues with what is being ripped.

Turn on debug logging and show us what errors you're getting besides the AV sync, please.

MakeMKV v1.16.5 win(x64-release) started
Debug logging enabled, log will be saved as C:\Users\mw/MakeMKV_log.txt
Using direct disc access mode
Title #1 was added (11 cell(s), 1:47:03)
Title #2 has length of 61 seconds which is less than minimum title length of 120 seconds and was therefore skipped
Title #3 has length of 74 seconds which is less than minimum title length of 120 seconds and was therefore skipped
Title #4 has length of 115 seconds which is less than minimum title length of 120 seconds and was therefore skipped
Operation successfully completed
Saving 1 titles into directory C:/Video/POIROT_SERIES6_DISC1
DEBUG: Code 0 at 1Qdz,F)Zsi!CiB0<z:213130237
DEBUG: Code 4294966822 at ;_f9#/b4hPJ&JP1#8pml:213143669
DEBUG: Code 0 at ;_f9#/b4hPJ&JP1#8pml:213140702
DEBUG: Code 0 at _Y+8iB|^MtysP|GFt:}V/:213137068
DEBUG: Code 0 at 3B#\%:BlUEu3k2A;:213132537
DEBUG: Code 0 at _Y+8iB|^MtysP|GFt:}V/:213137068
DEBUG: Code 0 at ?X91v,pcw_IIt^>v7:121264464
DEBUG: Code 0 at ?X91v,pcw_IIt^>v7:121263912
DEBUG: Code 0 at ?X91v,pcw_IIt^>v7:213130145
DEBUG: Code 0 at _Y+8iB|^MtysP|GFt:}V/:213137068
LIBMKV_TRACE: Exception: Error in p->FetchFrames(2,true)
Failed to save title 0 to file C:/Video/POIROT_SERIES6_DISC1/title_t00.mkv
0 titles saved, 1 failed

Those are not AV Sync messages, they're issues with the reading of the disk.

Start with the "ripping errors" topic at the top of the Bluray forum for things that can help with read errors.