Symptoms
If you try to move a public folder that has large hierarchy in Microsoft Exchange Server 2019 or Microsoft Exchange Server 2016, you experience an OutOfMemory exception from StringBuilder.ToString() in the Save ICS sync state.
Resolution
To fix this issue, install the following cumulative update, as appropriate:
Cumulative Update 10 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
Cumulative Update 21 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
References
Learn about the terminology that Microsoft uses to describe software updates.
