"Project has been used by MacOS, cannot be opened" approach

A few days ago in MacOS in the NTFS format of the mobile hard disk (in fact, the old computer to dismantle the hard drive down a shell) copied a few video. Today, when I want to open it, I find it is not open, and it is grayed out when the file is selected in the Finder.

Whether it is open in the Finder or in the video player, it is a hint that "item XXX has been used by MacOS and cannot be opened." Attempts to replicate locally are not possible (Finder or CP). However, the LS discovery file attribute has the "@" flag (that is, with extended attributes):

This property can contain many extended attributes (metadata), could it be the problem of this attribute? Take a look at the xattr, then. Use "xattr-l xxx.mp4" to list the extended properties of the file:

$xattr-L May days \-\ I don't want you to be alone \ (Tomorrow edition \). mp4
Com.apple.FinderInfo:
00000000 6F 6B 4D (a)------------XX |brokmacs........|
00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000020
Com.apple.avkit.thumbnailCacheEncryptionKey:
00000000 AA 0B 2D 4 a C9 BF FC ten 8D CA 7E E4 DB 85 |.. -j ... 9...~d...|
00000010
Com.apple.avkit.thumbnailCacheIdentifier:
00000000 E4 F7 EA 4C FF 0A CC 4 B 98 A1, C8 |DD....L....K. b.|
00000010
Com.apple.metadata:kMDItemDownloadedDate:
00000000 6C (A1)------|bplist00 3a.5..|
00000010 D8 5E 0A 00 00 00 00 00 00 01 01 00 00 00 |6.^.............|
00000020 00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 |................|
00000030 00 00 00 00 13 |.....|
00000035
Com.apple.metadata:kMDItemWhereFroms:
00000000 6C (A2) 6F one-up |bplist00...o....|
00000010------3 a 2F 2F |h.t.t.p.s.:././.|
00000020 6E 6A (XX)-----------
00000030 2E 00 62 00 61 00 69 00 64 00 75 00 70 00 63 00 |.. b.a.i.d.u.p.c.|
00000040 2E, 6F, 6D, 2F, xx |s...c.o.m./.f.i.|

Will find that there is a "com.apple.finderinfo" attribute, the content is "brokmacs", is estimated to be his reason. Use "xattr-d com.apple.FinderInfo xxx.mp4" Delete this attribute is OK, can open.

"Project has been used by MacOS, cannot be opened" approach