| Subject | English | Welsh |
| comp., MS | error bar | bar gwall (Usually used in statistical or scientific data, an error bar shows the potential error or degree of uncertainty relative to each data marker in a series) |
| comp., MS | error code | cod gwall (A return code that begins with E_ or DB_E_ and indicates that the method failed completely and was unable to do any useful work. Usually indicates a programming error) |
| comp., MS | error code | cod y gwall (One of four fields of an SCODE. It is a unique number that is assigned to represent the error or warning) |
| comp., MS | error log | log gwallau (A file that lists errors that were encountered during an operation) |
| comp., MS | error value | gwerth gwall (A value shown in Excel when there is an error in a formula, for example VALUE! or REF!) |
| comp., MS | Windows Error Reporting | Cofnodi Gwallau Windows (The Windows technology that collects data on system crashes or hangs and sends it to Microsoft) |