Policy
Set maximum number of trust records to preserve
This policy setting allows you to specify the maximum number of trust records to preserve when the purge task detects that this application has trusted more than the number of trusted documents set by the "Set maximum number of trusted documents" policy setting. If you enable this policy setting, you may specify the maximum number of trust records to preserve, with an upper limit of 20000. Due to performance reasons, it is not recommended to set it to the upper limit. If you disable or you do not configure this policy setting, the default value for of 400 is used.
f285a54a543b L_SetMaximumNumberOfTrustRecordsToPreserve Registry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\word\security\trusted documents\maxpreservetrusteddocuments Policy notes
This policy setting allows you to specify the maximum number of trust records to preserve when the purge task detects that this application has trusted more than the number of trusted documents set by the "Set maximum number of trusted documents" policy setting. If you enable this policy setting, you may specify the maximum number of trust records to preserve, with an upper limit of 20000. Due to performance reasons, it is not recommended to set it to the upper limit. If you disable or you do not configure this policy setting, the default value for of 400 is used.