# Causes of run-time errors for macros

At run time the application logs errors and warnings about macros to diagnostics under these circumstances:

- problems reading the macro file or the expression
- problems writing to the tag
- problems communicating within the project or with the data source

The application also sends information messages to diagnostics when an expression in a macro is read successfully, and when a value is written to a tag successfully.

Tip: | Because macros are not necessarily run in the order in which they are listed, do not rely on the order of execution to control your process.

## See also

About macros

data source