From the Microsoft 365 Admin Center - Service Health Page:
Title: Excel client crashes
User Impact: Users may encounter Excel client crashes in several scenarios.
More info: Users may encounter crashes in scenarios such as printing, executing macros, and using zoom, among others.
Current status: Reverting the build to the last working iteration is taking more time than initially expected. At this time, we suspect that it should complete on Friday, January 17, 2020.
Scope of impact: This issue may affect any Insiders Slow users of Excel on a non-English language version 2001 with build 12430.20050 and running the 32-bit version of Excel.
Start time: Tuesday, January 14, 2020, at 1:18 PM UTC
Root cause: A recent build deployment is causing client crashes with the Excel client in several scenarios.
Next update by: Friday, January 17, 2020, at 6:30 PM UTC
January 17, 2020 12:26 AM
Title: Excel client crashes
User Impact: Users may encounter Excel client crashes in several scenarios.
More info: Users may encounter crashes in scenarios such as printing, executing macros, and using zoom, among others.
Current status: Reverting the build to the last working iteration is taking more time than initially expected. At this time, we suspect that it should complete on Friday, January 17, 2020.
Scope of impact: This issue may affect any Insiders Slow users of Excel on a non-English language version 2001 with build 12430.20050 and running the 32-bit version of Excel.
Start time: Tuesday, January 14, 2020, at 1:18 PM UTC
Root cause: A recent build deployment is causing client crashes with the Excel client in several scenarios.
Next update by: Friday, January 17, 2020, at 6:30 PM UTC