Both the Taishō edition of the Chinese Buddhist canon and CBETA are commonly used by contemporary Chinese Tripitaka researchers. However, they contain quite a few errors. Although most of the errors are unable to change the central idea of a sūtra, some errors may cause scholars to misread or mistranslate certain verses. Although some scholars have discussed the errors found in the Taishō and CBETA, they have not systematically traced their causes. This paper takes Lokakṣema’s translation of the Pratyutpanna Samādhi Sūtra (T418) as an example, and collates the versions seen in the Taisho and CBETA with the editions they are based on, including the Koryŏ, Tokyo, and Pin Jia Zang editions. Having tried to find out all the errors contained therein, I traced their original causes. The results show that the errors contained in these editions can be divided into five categories: errors starting from the Koryŏ edition, errors starting from the Tokyo edition, errors starting from the Pin Jia Zang, errors starting from the Taishō, and the errors starting from CBETA. It can be seen that some errors are caused by the Taishō and CBETA themselves, but there are also a large number of errors copied from previous editions. Such a result is also applicable to other sūtras. This paper suggests that researchers should pay careful attention to the errors and their causes in the Taishō and CBETA, so as to reduce the chances of misreading and mistranslation, and even to create a more reliable version of a sūtra.