Same problem :-( Process: Keychain Access [855] Path: /System/Applications/Utilities/Keychain Access.app/Contents/MacOS/Keychain Access Identifier: com.apple.keychainaccess Version: 11.0 (55281.40.7.0.1) Build Info: KeychainAccess-55281040007000001~164 Code Type: X86-64 (Native) Parent Process: ??? [1] Responsible: Keychain Access [855] User ID: 501 Date/Time: 2020-11-13 16:13:09.783 +0100 OS Version: macOS 11.0.1 (20B29) Report Version: 12 Anonymous UUID: 6E5D9F33-6EDA-A53B-4BB6-1677B2D34BFE Time Awake Since Boot: 950 seconds System Integrity Protection: enabled Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXCBADINSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Exception Note: EXCCORPSENOTIFY Termination Signal: Illegal instruction: 4 Termination Reason: Namespace SIGNAL, Code 0x4 Terminating Process: exc handler [855] Application Specific Information: dyld3 mode

This works for me: I checked my keychains in terminal with command: security list-keychains There were two keychains with invalid path on my computer, "Apple Development" and "Mac Developer" keychains in /private/var/... folder. I deleted the the two keychains in terminal with command: security delete-keychain [keychain with invalid path] Some message was displayed, but keychain was successfully removed. security: SecKeychainDelete: UNIX[No such file or directory] Now Keychain access works again. I hope this helps.

@andre.ferreira.ais your keychain path contains space character try inserting double quotation mark around your keychain path try this: security delete-keychain "/private/var/folders/2q/0ccsr2p11qz6c2wh8qtpm80000gp/T/Apple Development: André Santana (André Santana)~~~6r9ipc/Apple Development: André Santana (André Santana).keychain"