[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間:2025-09-04 (世界標準時間)。"],[],[],null,["# Troubleshoot issues with Migration Center discovery client CLI\n\nThis page shows you how to resolve issues with the Migration Center discovery client CLI.\n\nUpgrade issue\n-------------\n\nWhen you upgrade the `mcdc` CLI to the latest version, it\nperforms an internal database schema upgrade which automatically creates a\nbackup of collected and assessed data by the previous version.\n\nIn rare cases, the `mcdc` CLI upgrade doesn't complete\nsuccessfully due to a failure in upgrading the local database. This might happen\ndue to a malfunction during the database upgrade which corrupts the database,\nand therefore, the previously collected data is lost.\n\nAfter upgrading the `mcdc` CLI, when you run the latest\nversion, if you see an error which indicates that the database upgrade failed,\nyou can use the `recover-db` command to restore the database to a previous\nworking version then downgrade to the previous `mcdc` CLI\nversion.\n\nPerform the following steps:\n\n1. Restore the database to a previous working version:\n\n ./mcdc discover recover-db\n\n2. [Download](/migration-center/docs/download-collector-cli) the\n the `mcdc` CLI version you used before the upgrade.\n\n While installing an older version the `mcdc` CLI, don't\n remove the `mcdc` CLI directory that is created by the\n current version.\n | **Note:** On Linux machines, the lowest version of `mcdc` CLI that you can downgrade to is version 2.0.0."]]