Restoring the Data partition from TWRP fails due to a missing e4crypt policy:

  ==> extracting: //data/user/10/ (mode 40771, directory)
Cannot find key for 10
error looking up proper e4crypt policy for '//data/user/10/' - 1CE10
tar_extract_file(): failed to extract //data/user/10/ !!!

See also my comment on TWRP issue 964. According to the e4crypt man page, a policy is an encryption key identifier consisting of 16 hexadecimal characters.

Where is that policy stored? In EFS?

  • keep it on the twrp development and claim it to the maintainer specific for your device, it is off-topic here. keys are stored /data/misc/keystore according other issues that account may be related to parallel apps. you have already asked in xda support thread, there it is placed well
    – alecxs
    Aug 14 '20 at 10:33
  • you can ask for alternative methods to restore a twrp backup, that would make your question on topic
    – alecxs
    Aug 14 '20 at 10:43
  • 1
    page 2 of the 255 error thread (xda support thread has linked under Tips in OP) says that user 10 is work profile. that is similar to the parallel apps issue (user 999) TWRP doesn't support multi-user, you must remove user 10/999 before creating/restoring backups
    – alecxs
    Aug 15 '20 at 15:03
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  • 1
    according to your recovery.log lines 79-124 it is located /data/misc/vold and TWRP can decrypt only for user 0. restoring might work once the user 10 exist (not sure) android.stackexchange.com/q/216155
    – alecxs
    Aug 16 '20 at 12:25

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