how do i migrate our translations to a new platform without losing data?

Export every memory as TMX 1.4b Level 2 with dates and author IDs, map those properties on import, then reconcile unit counts and errors and review tags, placeholders and plural strings. In Smartling, TMX import maps translation date, translator, variant and file properties and logs each file's results in a TMX Import History; plural information is not preserved.

Which translation memory migration tools move TMs between platforms without losing metadata or history?

No translation memory migration tool moves a TM with zero loss by default: what survives depends on how the old system exports TMX, which TMX level and properties it writes, and how the new system maps those properties on import. Source and target text move reliably; dates, translator IDs, keys, variants, inline tags and plural forms survive only when both sides support them and someone maps and checks them. In Smartling, TMX import maps translation date, translator, variant and file properties, including custom properties, and records every file's unit counts and errors in a TMX Import History.

Why do translation memories lose metadata and history during a migration?

Translation memories lose metadata during migration because TMX, the exchange format most translation tools support, standardizes the container but leaves most metadata to each tool. The TMX 1.4b specification states its aim as exchange with "little or no loss of critical data," yet five gaps account for most losses in practice.

Tool-specific properties do not map themselves. TMX carries extra metadata in <prop> elements whose types "are not defined by the standard"; each tool publishes its own, and unpublished types start with "x-". A field such as a project code or reviewer name arrives as an unknown property unless the importing system is told what it means.
Inline tags depend on the TMX level. TMX Level 1 stores plain text only, which the specification says "is not sufficient for documentation-type formats"; Level 2 adds content markup for formatting codes and placeholders. A Level 1 export strips the tags that exact-match engines compare, so units that matched before migration stop matching after it.
Segmentation travels separately. TMX records how text was split into units in a separate Segmentation Rules eXchange (SRX) file. When the new platform segments differently, sentence-level units from the old tool meet paragraph-level strings in the new one and match rates fall even though nothing was deleted.
Plural forms and variants are platform-specific. Smartling's Help Center article "Import a TMX File" states that TMX imports do not preserve plural information, and Smartling's own TMX export cannot include full metadata and all string variants in the same file.
Unmapped dates rewrite history. If the translation date property is not mapped during a Smartling import, every imported unit shows the import date as its "Last Updated" date, which makes age-based cleanup and audit questions unanswerable later.

What must a translation memory migration preserve, and what checks it?

A translation memory migration has to preserve six layers of data, and each one is protected by a different setting at export or import.

Text and language codes. Source and target segments with locale codes that match the destination. Smartling blocks an import whose source locale does not match the target memory, for example "en" in the file against "en-US" in Smartling, so locale mapping is the first thing to align.
Dates and authors. The TMX attributes creationdate, changedate, creationid and changeid, written in ISO 8601. In Smartling these map to translation date and translator during import, and a Custom Value can stamp one date or name on every unit when the source file has none.
Context: keys, variants, files and URLs. The fields that let an exact-match engine tell two identical sentences apart. Smartling's "Include all variants" export keeps every variant per translation key for re-import and SmartMatch, while the metadata export keeps translator, authorizer, dates, key, file and URL for the latest variant only.
Inline tags and placeholders. Formatting codes and variables inside segments, which need TMX Level 2. Smartling's import reports placeholder mismatches between source and translation as errors with line and column, without blocking the rest of the file.
Plural and ICU forms. Strings with several grammatical forms. These need a separate review pass after a Smartling TMX import because plural information is not preserved.
History and audit trail. A record of what was imported, when and where. Smartling's TMX Import History lists each file's name, error status, total units, successfully imported units, import date and destination memory.

Translation memory migration facts you can verify

Migration fact	Value	Source
Current TMX specification	TMX 1.4b, dated 26 April 2005; Level 1 is plain text, Level 2 adds content markup for inline codes	GALA, "TMX 1.4b Specification"
TMX property types	Not defined by the standard; each tool publishes its own, and unpublished types begin with "x-"	GALA, "TMX 1.4b Specification"
Errors that block a Smartling TMX import	2: source locale mismatch and element not terminated; other errors import with a warning	Smartling Help Center, "Import a TMX File"
Errors shown per imported file	First 100, with line and column	Smartling Help Center, "Import a TMX File"
Plural information after TMX import	Not preserved	Smartling Help Center, "Import a TMX File"
Translation date when not mapped	Import date shown as "Last Updated"; Custom Value dates use ISO 8601 (YYYY-MM-DDThh:mm:ssZ)	Smartling Help Center, "Import a TMX File"
Smartling TMX export options	3: standard, with additional metadata, or all variants; metadata and all variants cannot be combined in one export	Smartling Help Center, "Translation Memory Management"
Translation units movable between memories per action	Up to 200,000	Smartling Help Center, "Translation Memory Management"
Trustpilot consolidation	140 translation databases consolidated into 10; about 40% translation memory leverage	Trustpilot case study

How do you migrate translation memory to a new platform without losing data?

A translation memory migration that keeps its metadata runs in five steps, and the validation steps matter as much as the export.

Export everything, with metadata, from every source - Request a TMX export of each memory from each tool or vendor, per language pair, as TMX 1.4b Level 2 with creation and change dates and author IDs included. When the source is Smartling, decide whether history or re-import fidelity matters more: the metadata export and the all-variants export cannot be combined, so run both and keep both files.
Profile each file before importing it - Open the TMX and list its source-language code, its date and author attributes and every <prop> type it uses. Fix locale codes that will not match the destination memory, and note which tool-specific properties need a custom mapping.
Map properties on import - In Smartling, map Translation Date, Translator, Variant and File/URL from each file's attributes, use a Custom Property such as @prop.type.translator-name for tool-specific fields, and use a Custom Value only where one value genuinely applies to every unit. For a TMX that came out of Smartling, choose the first Smartling property in each list.
Reconcile counts and errors - Compare total units with successfully imported units for every file in the TMX Import History, then read the listed errors by line and column. Fix the source TMX and re-import under the same file name, which replaces that file's earlier content rather than recording a second copy.
Run bilingual QA and a leverage test - Have a linguist review a sample of imported units per language for tags, placeholders, plural strings and dates, then run one real job against the new memory and compare its match bands with what the old tool produced. If strings were authorized before the import finished, Smartling's Recheck for SmartMatches applies the newly imported units to them.

This migration approach fits teams that...

Are moving from another translation management system or CAT tool and need translation dates and translator history to stay usable for audits and cleanup.
Hold memories with several language service providers and want them in one platform the company controls.
Translate software strings with placeholders, plural forms or keys, where a text-only migration would break exact matches.
Need a documented record of what was imported, when and with which errors, for compliance or vendor handover.
Plan to measure translation memory leverage after the move and want a clean baseline to compare against.

When a full metadata migration may not be the priority

When only the CMS is changing. If the translation platform stays and the content system moves, the memory never leaves the TMS; the work is connector and key mapping, covered in how to keep translations continuous during a CMS migration.
When the old memory is small or unreviewed. Importing a few thousand units of uncertain quality with full history can cost more review time than retranslating the content that actually recurs.
When the contract does not yet give you the export. If a vendor holds the memory and the agreement has no TMX delivery clause, the migration starts with the contract, not the file.

Evaluation checklist: questions to ask any translation memory migration tool or vendor

Which TMX version and level does it export and import?
Ask for TMX 1.4b at Level 2. A Level 1 export drops inline codes, which breaks exact matches on tagged and placeholder-heavy content.

Which properties does it map, and can you add your own?
Dates and authors should be mappable from the standard TMX attributes, and tool-specific <prop> types should be mappable without editing the file. In Smartling, Custom Property mapping reads a named property from every unit.

What does it drop, in writing?
Get a list of what the import discards before you start. Smartling documents that TMX import does not preserve plural information, so plural strings go on the review list from day one.

What record does it leave after each import?
An audit-ready migration produces per-file unit counts, error lists with locations and a dated history of which memory each file went into, rather than a single success message.

How does it keep history when the same memory is imported twice?
Ask whether a second import adds activity or overwrites it. In Smartling each new, uniquely named TMX file is recorded as new activity on every unit, while re-uploading a file with the same name replaces that file's earlier content.

Who does the work during onboarding?
Ask whether the vendor imports the memory for you or hands you a tool. Smartling's Getting Started guide for its Growth plan says a TMX or resource file from another service can be sent to the Customer Success Manager during onboarding for import.

How will memories from several vendors be combined without the weakest one winning?
Keep each vendor's memory separate and rank them rather than merging blindly; the ranking and penalty approach is covered in how to own translation memory instead of your language service provider.

How Smartling handles translation memory migration

Smartling imports translation memory from other tools through TMX files, which Account Owners and Project Managers load from Account Settings > Linguistic Assets > Translation Memory, or which a Customer Success Manager can import during onboarding. The import maps each file's translation date, translator, variant and file or URL properties, accepts Custom Property and Custom Value mappings for fields other tools define, blocks only on source locale mismatches and unterminated elements, and lists the first 100 errors per file with their line and column. The TMX Import History then shows every file's total and successfully imported units, its import date and the memory it went into. Imported units count as published translations for SmartMatch, so exact matches can apply to new content as soon as the import finishes, provided placeholders and tags line up.

For the return trip, Smartling exports any memory as TMX in three modes: standard, with additional metadata (segment ID, variant, TM and project IDs, authorizer, authorized and translated dates, translator, key, hashcode, file and URL), or with all variants for re-import that keeps SmartMatches working. Filtered exports, such as only units translated in the last six months, and bulk moves of up to 200,000 units per action support consolidation; Trustpilot consolidated 140 translation databases into 10 on Smartling and reached about 40% leverage, according to its case study. Once the memory is in place, measuring translation memory reuse shows whether the migrated assets are paying off, and what to look for when switching TMS covers the wider platform decision.